1993 seems to be the year. BTW, the M60-7 is the very best Chief's Special variation they have ever made - IMHO of course. I have one myself and it's fantastic!. It is everything you want in a revolver and nothing you don't! It was my carry piece for decades - up until 6 years ago when I switched to a P365 - but that is a story for another thread.
Thanks for the info guys.
I transposed the s/n in my op so it might have shipped a little earlier.
I'll post a pic whenever it stops raining here so I can take a decent one.
The database doesn't list any Model 36-7s with BFP serials, but
Model 60-7s BFP4865 shipped in November 1990 and BFP8932
probably shipped in early 1991.