Do the trade before that person comes to their senses. And the going rate on GB for that pistol is higher than the $900 that bigmoneylewis says. You can put that north of $1000 in that condition nowadays. even without box and tools. I bought a nickel 27-2 8 3/8" off GB a few months ago for around $1200, but it also had TT and TH besides the target stocks and was in the wood presentation case and was unfired except for the 3 test rounds. It's no longer unfired.
EDIT: As to age, that was manufactured in the 1973 to 1974 time frame most probably. I have a 5" 27-2 with a serial of N168XXX that I bought new in April 1974.