Marlin mod. 90 O/U 20 gauge

[JamesleeT]

Hello all JamesleeT here and new to the site.
I have my eye on a 1957 model 90 in 20 gauge with 2 triggers and checkered wood. It looks pretty good but with a little neglect causing minor rust in a couple of places.It is overpriced but I am really interested in it although I do not know anything about the 90's concerning overall quality, reliability or actual value. Are they collectable and something worth spending my grandchildren's inheritance on?

Thanks for any input or even a kick in the right direction.
JamesleeT.