Bob Drake water pumps

[PhoenixFear]

I tried calling Bob Drake but got tired of waiting on hold. The water pumps on my truck have a casting that says DCM 8504 and DCM 8503. Bob Drake has some pumps listed but their part numbers are 8RT 8501 and 8502, as well as 78-8501 and 8502. The site says they are for use with 49-53 engines going into earlier vehicles, which is exactly what I have. Would these pumps work? Thanks.