If the tank is mounted on the mower deck, then yes, it would be a crankcase pressurized fuel system.
I have seen a some photos of different Jacobsen Bantam's over the years, and I remember a couple of them having odd color schemes that you mention. I remember wondering at the time if that was originally how they were painted from factory because obviously most Jac products were painted pure orange back in the day. My guess is that since a few of these models have been seen to have a different color scheme that is how how they were painted, atleaste for a certain time period.
You should also be able to tell if the paint is original or not. Scrape a little off in a inconspicuous spot and see if there is orange underneath.
I have seen a some photos of different Jacobsen Bantam's over the years, and I remember a couple of them having odd color schemes that you mention. I remember wondering at the time if that was originally how they were painted from factory because obviously most Jac products were painted pure orange back in the day. My guess is that since a few of these models have been seen to have a different color scheme that is how how they were painted, atleaste for a certain time period.
You should also be able to tell if the paint is original or not. Scrape a little off in a inconspicuous spot and see if there is orange underneath.