Collect?
I'd get 'em running and put them to work.
For the money, you could certainly get two running mowers out of the deal and end up with another that really is collectible which you could then flip to an LB enthusiast.
My old Lawn Boy was the most pleasant mower I've ever used.
It never bogged down in even the heaviest grass and always gave a nice even cut.
The lack of oil to chnage was another advantage, although maybe not with this crowd.