New "Freon" Problem

[imp]

Can anyone help with this one? We got a 1993 Van awhile back, and now want to start using it- (Ford E-150). No info underhood on whether it is charged with Freon 12 or new-fangled 134a. The Ford 1993 Shop Manual says clearly F-12. However, the system is equipped with the access ports which accept quick-disconnects, which I thought were only used with 134a. The older systems had smaller, threaded ports.

 

It clearly needed additional charge, high-side showing about 100psi at ambient 80 degrees F.

 

Does anyone know, whether the presence of the newer ports signifies 134a?

 

Is there any simple way to determine what material is in the system?

 

Thanks, in advance, for any help. imp

 

Edit: What might result from mixing of F-12 and 134a in the same system?