Hi Mike,  
During an unexpected "culo de pollo" west of Nicaragua, I lost the port roller of my genoa car on my sailing from Panama to Cancun Mexico. I was lucky that the bolt tube and nut were miraculously laying on the deck and I was able to create a temporary solution  (see pic). 
Do you know the exact serial number of the Antal Part that fits your SM.  Mine is #178 which may be different but should fit the same track.

Jose Gabriel Venegas
Ipanema SM2K  #178
Currently at El Cid Marina, Cancun, Mexico