1937 GBD R9239 Rhodesian (9242??)

This shape is a bit of a GBD mystery. In the past six years, I’ve seen three of these come up on Ebay (one was unsmoked!). All of them have the R9239 designation, with a London hallmarked band that dates to 1937 (B date code). I have two other hallmarked 1930’s era GBD’s and each has the R code in front of the four digit shape number. The 9239 is referenced no where else in any GBD catalogs or literature that I’ve encountered. I speculate that the R must have signified a silver hallmarked band, but unfortunately that detail is lost to time.
Winning this auction was a battle with 12 other bidders and I eked out a victory by a few dollars. I studied the sellers photos carefully before bidding and I had plenty of apprehension until it was delivered. As you can see below, the photos were either altered digitally or the flash made some odd patterns on the briar. The rest of the pipe looked solid enough to allow me to bid. On delivery, all of my fears disappeared. The briar and vulcanite were in terrific condition. The stem fitment was snug with zero bite marks on the oxidized stem. The odd shadow was just that, a flash mark or other.
Here's the sellers photo and one that I took.



And the finished pipe below. Full details are the Reborn Pipes site

https://rebornpipes.com/2017/12/01/1937-gbd-chubby-rhodesian-r9239-restored/

Looks silver colored to my eyes.

But to me, silver would be considered "normal".

That is a good question, unfortunately, I don't think it has an answer.

I can tell you that on the older GBD's, the rondell is smaller by about 1.5 mm than those on what I would consider to be more modern. (and as such, hard to work around!)