Radiation (off the face) was measured with several different calibrated instruments. They are indeed hot, especially the latter models (TBY-8 hotter than TBY-1). The OSHA allowed personal radiation dose is easily exceeded if one were to be within a few feet of the faceplate for a period of many hours. Of greatest concern is particulates that may be inhaled or else transferred to the mouth or eyes via hands. If you look closely at the lettering with a magnifying glass you will notice that the surface is not smooth, but sponge-like. Alpha particles have broken up the paint structure leaving that surface material friable. Within the body alpha, beta, and gamma are all of concern....especially alpha. At distance the radiation species of concern is mostly gamma as alpha doesn't travel far at all and beta doesn't penetrate the skin very far.
OSHA allowances for non-occupational individuals are quite low in terms of both rate and total annual dose. It's easy to exceed them with a CAT scan. However, occupational allowances are 50 times higher! No, military collectors are not an official occupational category :-)
Bottom line is to use caution with TBY's. A clear coat over the front panel and tuning drum lettering would go a long way to mitigating the most dangerous situation....particles lodging in the body. As for the beta and gamma: Well, an 1/8" of aluminium blocks most of the beta but in order to stop the gamma it takes sheet lead or thick leaded glass, both of which are commercially available with the latter being pricey. Otherwise, keep at least 3 feet away if you're going to be near a TBY for many hours. Remember that radiation falls off as the square of distance. That translates into budgeted restoration hours for collectors that have to get very close for their work. And please don't use compressed air on them without being well out in the open and wearing a mask. Best to not use compressed air at all. Finally, I would suggest that TBY's be long-term stored in a bag in order to contain particulates.
I am not aware of any radiation induced health issues among the code talkers, but that doesn't mean it didn't happen. We all know about the terrible situation of the ladies that brushed on Radium 226 infused paint (direct ingestion). Knowledge of radiation effects on the body only grew in the decades following WW2. Today, the area of most concern is the increased usage of medical scans.
Dennis AE6C