I got into the sport in the mid to late 80's. I had the Gita catalogues of that period & may still have some around somewhere. All of the De Rosa offerings from 86 on up all offered flat fork crowns. That was the most notable feature of those bikes.I seem to remember DeRosa putting out a couple of different commemberative bikes in the '90's, of which this one seems to be one of. At least that's how it seems to me.
An ,82 would probably have had a chainstay bridge, not a braced bottom bracket. Also, SL tubing not SLX, especially on such a small frame.
My early '80s has a slopping fork crown and a chainstay bridge but my mid '80's, maybe '85, has a braced bottom bracket and a flat fork crown. Both are SL tubing and are 58mm frames.