i dont know about the columbias but the schwinns with the lock has a notch in the bearing cups on the inside (for the tumbler i think.......)have you pulled the cups out yet? that might tell you
i say go for it a long time ago when i was more into original bikes i had a few girls bikes and one day i said to myself "why do i have these i would not be caught dead ridding them." then i built my first rat using parts from one so there ya go. i say go for it heck this is getting to be the only way to find cool forks and such so why not we are all rat rodders after all?
those fenders look in really good shape, other than the surface rust. It's hard to find fat fenders in that good of shape. I'm sure you could get some money from them on the bay or on the classifieds here.