Previous part numbers with West Marine were as follows;
316226 - small swing out mount
252389 - medium
252371 - large (the one I bought shown in pic above)
They still stock the Ram units
319154 - swing arm with vertical base and pivot plate
319160 - extension arm
I think if you call their order desk, they may have some of the older units in the first list
www.westmarine.comCheers
Tim
