Well the phase 1 willys came with a plaque on the dash with its number on, where the rear window heat switch, rear fogs etc switch is, directly underneath should be the plaque if it is a phase 1.
TBH, itd be worth gettin the AA to check it over cos repairs can be expensive. Check rear archs for rust, even if you see just a tiny blip it could mean the whole rear arch is rusted up.