Is Baja even in business any longer? If i'm not mistaken Fountain bought them then I thought shortly after they went out of business. I could be totally wrong about that though.
Even if Baja is still being made by Fountain im fairly certain they moved production from the original Baja factory which I think was in Ohio to Fountains shop in NC. So I really doubt they held on to any of the older parts even if they had them at the time.
Im thinking your best bet if you want to get that exact swim step is to hunt Ebay for possibly a wreck or something being parted out. Or have one custom made. Based on the images I saw online it looks pretty complex so you would probably need a really good fiberglass guy to pull it off.
Now that I had a second to look it up im positive that Fountain makes Baja. So the Baja brand is still alive which is good but does appear they are being made in NC. Its worth a shot to call them but im doubting they will be much help.