most tourist goods are highly decorated, made of lighter softer woods and designed to be hung on a wall.

What you appear to have is a serious working boomerang that looks like it's seen service.
It would have sufficient decoration to aid in it's use, but nowhere near as much as a purely decorative piece would have.  

IF you look at this site. You can see the similiarity to your own.
http://www.flight-toys.com/throwsticks.html

here's some more




The info on this site is worth a read.
http://www.objectlessons.org.uk/default.asp?Document=200.0070.0020&Image=AUS881X...

Your boomer looks as authentic as anything on any of the sites I've seen

  I also think it does look a little "antiqued".  I don't think it was made just a year or two ago.
  That's an awesome collection of throwing sticks you have there ardvark!  I have some pieces of white and yellow birch drying out right now I will be carving into some.

Looks reasonably genuine from the toolmarks, and the colour, grain and form is consistent with centralian work.

Those supersharp ridges among the finish are, as paleo points out, inconsistent with stone tools. However, a lot of central desert mobs finish with incisor teeth (sometimes still mounted in a jawbone, for grip) and it leaves those regular, almost hypnotic patterns. Some artists use modern steel tools to achieve the same results... think "lino-cutting" tools

Coverage of artwork does not mean a whole lot... some tourist pieces here are entirely "plain" and others are heavily ornamented... but more typically in gloss acrylic or enamel paints, rarely ochre as some of your pictures seem to indicate. Of course, 45 year old acrylic looks a lot like ochre in a photo. Try rubbing the artwork on a small area, and rubbing your finger on your teeth... if it scratches, it's stone mineral.

Not all Aboriginal Australian boomerangs/throwing sticks are made from the classic super dense hardwoods... plenty of our so called "soft timbers" are more than heavy enought to crack skulls or break ribs of small hopping game.

Very early "tourist" or "anthro" trade would have been ornamented in ochres rather than paints... but simply using ochre does not mean it is is a "real" item (ie, a used one...) as at one time it would have been more available to some tribes than western manufactured pigments. One of the most significant pieces of totemic cave art I have seen is done in (literally) what was once known as "blue chinese laundry chalk"... we use what we can find, here.

A good example of how "the normal" condradicts the "norm" is that everyone OS knows aussie indig art is about "dot painting". Thing is, almost all classic "dot art" is essentially an indigenous "Po Mo" movement... artists here at one time were basically told by elders to not use spirit art etc for sale or tourist market... so some "fragmented" them in dot form ( which is to say, before the marketable era NO central mob ever used dot art ) so they could still reproduce their cultural symbols without infringing "taboo" law

Think... a very low res thumb versus the original, glorious HD

Where was the "Estate sale" situated? A lot of semi-marketable goods were sent back to Europe and the US a LONG time prior to the very brief period where Australia was a US airbase Especially back along german and scottish family trees.

That "antiquing" look you mention is here called "silicon glazing"... basically stone or timber from around here, after being exposed to x amount of weathering and use shows up that real deep hard glassy gloss... it's the silica coming thru... joys of an aged continent.



t

  Well, I don't know whether they did this in Australia, but I know that many tribes would ornament their weapons with the blood of the first kill they made with it.  You could look it over and see if it had any smears or drops of blood on it, that might be hard to see but a darker smear or pattern of drops may be worth further investigation.  This would indicate it had been used.  Just a thought, probably isn't too brilliant though.