It's gotta be a round butt 2 and-a-half inch barrel. From what I've read on the forum, being in California and being an actual defense gun, its got to be worth a king's ransom!
Do you guys still use dollars, or euros? (or yen?) You may be able to trade it for a second hand Bentley!
sorry, I couldn't help myself...but seriously, there's lots of guys on the forum with familiarity on California prices...can you even sell it there, or does it have to go out of state? (I'm being serious now)...out of state, I suspect $550 to $650 depending on your market...they are a classic and about the greatest carry gun ever made w/ 6 shots...make sure you know about the pinned barrel & recessed cylinders, S&W stopped those extra features in 1982 or so as a cost cutting measure (they were found to be unecessary but sure add quality to the gun...yours has them, it was made around 1980)
I'm sure others will share their thoughts...welcome to the forum!! I hope you get a chance to experience the pride & joy of S&W ownership.