Decode early Fisher Body cowl tags?

[Pontiac59]

I have an old cowl that I suspect is 29 Pontiac closed car but no way to tell except the Fisher Body tag numnbers - a job number and body number. Job is 8558 (last 8 could be a 3) and body is 1058 (5 could be a 3 also, going by a fuzzy flash photo I took in the dark).

Anyone have a way to ID those numbers? My Krause Standard Guide to Pontiac shows model numbers that are 4-digit and begin with 8 but none have a 5 as a second digit.