If you wanted to send some pics of the proofs on the lower, the barrel proofs- under the HG's at the back by the flats, on the site base, trigger, etc (Should be a small circle with a number in it if its Steyr) If its under 20K serial number, its an Fn. FN made them for Austria until they were fully tooled up. They both are great, you can see the difference in the finish with the FN's beinig a darker black/ bluing vs the Parkerizing on the Steyrs.- I can tell you exactly what you have. (Hence the name STGguy)! lol.
The barrel will say "Kal", StLf3, Vol, etc.
The Grayslake ones for some are more desiriable, the fact is they are both Great Forged Uppers made by LMT- Grayslake or Lk Barrington proofs are just stamps of the city in Illinois that DSA was located in at the time. Some feel that LMT might have produced the best uppers under 20K or so Serial number.All the Grayslakes I've seen have been in the 10K range.