These guns come in alot of sizes:
10 ga 12lb 5 oz-have 2 other 10's @ 12lb
Have 2 double 8's 10 lbs even-not conversions
10 Hammerless 7 1/4 lb on the other end-original

MarketHunter I'm sure the heavy 12 you mentioned was a
Fred Abbey 12lb-saw the gun. Have seen another-same weight

M/L Conversions are lighter and often can not tell they
are Conversion-which may be the case here. To me it
doesn't really matter-still high quality workmanship.
Bill McPhail

J W McPhail