Saginaw Tail Housing Marking
 

Does anyone have a picture or knows the correct numbers for the Saginaw Tail Housing in a 1967 Firebird Sprint. The parts catalog shows 3873885 for all 66-69 OHC manual transmissions (both 3 and 4 speed). I found one that looks similar but the numbers were completely different and I am wondering if 3873885 is a GM part number and not a casting number. Thank you in advance.