Here is what I found out from the local Raleigh Dealer, (they have been a Raleigh Dealer for 103 years so I sort of trust them) I was told that the "All-Gold Editions" were in production from '68-'72, apart from having more "economy" parts, namely rims, tires, saddle and shifter, they also were "leftover" frames that had the weird bottom bracket threading (I think 24tpi but can't be sure) They were painted gold so that mechanics would use older (from the 50's) bottom brackets and headset parts when replacing them. I don't know how accurate this is, but makes sense. Still it is a really cool old bike that shares parts with the older Raleighs. Just be careful when replacing a bottom bracket or headset.