U87A differences

Hey folks,
I just scored an almost never used U87A from Ebay for 600€.
I can't seem to find much information about this Version. Only, that it is in fact an U87Ai...  Is that true? Does someone know any differences between the U87Ai and this one?
Neumann states, that it was manufactured between 1986 and 2011.
As I would like to use the capsule and switch assembly for an U67 clone, does someone know, if it is possible to build a vintage U87i  with k87 capsule, out of the circuit board and transformer from the U87A?

http://recordinghacks.com/microphones/Neumann/U-87

"Four versions of the U87 were initially released by Neumann:

    U 87 - grey/silver finish, 7-pin Binder/Tuchel connector
    U 87 i - grey/silver finish, 3-pin XLRF connector
    U 87 mt - dark gray finish, 7-pin Binder/Tuchel connector
    U 87 i mt - dark gray finish, 3-pin XLRF connector "

http://recordinghacks.com/microphones/Neumann/U-87-Ai

"Neumann

The circuit for the U-87Ai uses a DC-DC converter, which the original [U-87] did not. This allows for higher internal
voltages to be stabilized from the 48v supply, which in turn allows for better noise figures and more dynamic range. The U-87Ai gives 6dB lower noise and 10dB more signal to noise than its predecessor."