The reference 7924 shares a similar fate to it’s two older brothers – the 7922 and 7923. Short production run and unclear history. All the 7924’s seem to have 1958 casebacks. As with the 7922 they are featured in thick case / big crown variations and in thin case / 6mm crown variations.
The 7924 was most likely sold with Rolex stainless steel Ref. 7206 Rivit bracelets or the optional 6636 “stretchy” variation. The watch is 20mm between the lugs and the caseback uses the standard Rolex 29.5mm case opener.
The crystal on the 7924 is the tropic 17. Thereby it is grouped together with the Rolex 5510, 6200 and 6538. It is interesting to note that the 7924 shares crystals with the 6538 but not casebacks.
The movement is a cal. 390 Tudor movement. Originally produced by Fleurier. The movement is automatic, as nearly all Tudor Submariner movements. These movements exist in raw brass versions and in rhodium (or similar) silver like plating. There is vivid discussions in the collectors community regd. which movement platings is correct for what reference. In general almost all combinations have been seen. I have communicated with Rolex on this issue but not received an answer.
Military and civilian versions have been seen in the wild