Can anyone confirm that the R12 condensers in the older W124's are not as big/dense as the R134a condenser of the later model W124's?

For the 6-cylinder W124's, can I easily switch out the older R12 condenser with the newer R134a, or are there fitment and plumbing issues? Can I keep my single A/C fan, or do I have to go to dual-fans?

Thanks,
:-) neil
1988 360TE AMG
1993 500E