From a post on the subject "Widow Maker Rims" in the forum I'm made some changes to address some of the issues raised here. You may have read some or all of that thread.
I went through this same discussion on "widow maker" rims when I was trying to find out if I could use the original ones on my 49 1-ton. So below is a link to an article that you might find interesting and it seems to provide some details on what is, and what isn't, a "widowmaker" rim. Read the article on "Setting the Record Straight". Basically, none of the rims have been "outlawed" or "banned" per the article and the OSHA information I've been able to find. The 3-piece rims that are on my 49 don't seem to fall into the "widow maker" category, yours rims might, but it all gets down to the condition of the rim, regardless of how many pieces there are. And considering it's almost 40 years old, you might not want to take a chance anyway.
http://www.retread.org/PDF/SettingTheRecordStraight.pdf Here's some more information that you might find useful. This is the actual OSHA guidance on rim matching.
http://www.tireindustry.org/pdf/osha_Rim%20Matching.pdf This one has the mount/dismount procedures as well as some inspection procedure information.
http://www.tireindustry.org/pdf/osha_Demount-Mount.pdf Hope this helps and have a great holiday weekend.
