With the pre '81's, the recievers were indeed chrome-moly. They were thinner (hence strength of newer ones approaching the older), but the older ones had a different balance (more between the hands, less barrel heavy) and the wood was less "proud" on them. They were indeed trimmer and quicker handling. The two in .308 and one in .358 I've shot were acceptably accurate but not bench-rest accurate. I've missed out on buying both that .358 (sold by widow after death of owner, didn't have the money and relative wanted it....) and a .257Roberts (didn't have money then, either.....). Same problem I've had with Savage M99's too.... missed out on a .250 take-down with engraving at a pawn shop. A coworker snagged it (Major's w/30yrs make more than a probationary officer, fyi). His widow sold it for $$,$$$ after his death. $300 was over my head in 1981......$15,000 in 2003 also.....
My only aversion to them (both BLR and M99) was that it was difficult/impossible to mount the scope low enough to have good ergonomics with the stock which was clearly intended for open-sight use. To me they feel "clunky" and un-balanced (top heavy) with and don't point where you look with scopes mounted.
Also, extra magazines were extreamly expensive.....(BLR'S) 1/4 the cost of the rifle at one point...If you could find one. Availablity is better now, and price more reasonable, but not inexpensive.
I find the Marlins to be much better in the area of ergonomics (fit to shoulder and chin, even when scoped). And no $$$ magazine to lose.
Edited to add: In my 25yr career as a gamewarden, I saw more than one BLR with aluminum recievers that had the screw holes for scope mounts stripped out from over torqueing the screws...... Another reason to be wary of the aluminum recievers.....