The SBH ejector housing was made of steel until 1963. The alloy housing would be found on any 80-xxx gun, however that's no reason to have to live with that. The most reasonably priced and very well made steel ejector housing is made by Story. I believe Brownells may sell the Story housing. You have to stipulate what diameter screw it has, as there were two sizes, and there is the older version with the stud, which the alloy housing equiped barrel wouldn't have.
The 3 screw hammer had the widened spur, which the conversion kit does not have.
That is a very good price, jump on it.