Ok- this part of the jury had an early lunch (3am)a bit before brekky, and have now done some research, (messages received and replied to at the time, but my sent mail not saved, so not relevant here).
Maybe I didn't have access to a parts list at the time, but acquired same soon after, and have now revisited it.
... In the parts listings, there are 2 spring spacers shown, part number 67-4131 plunger (top) spring lower collar and 67-4127 rebound spring bottom collar, ......
My findings in the parts lists for '49-'53 & '54-57 show NO part #67-4131, but the following are listed;
5; 89-4257 Plunger Spring Top Collar (On TOP of Spring)
14 89-4258 Rebound Spring Bottom Collar (UNDER BOTTOM of Spring)
** 19 67-4127 Rebound Spring Top Collar **
Unless my eyes are deceiving me; ** conflicting information;-
.....and 67-4127 rebound spring bottom collar......
So I've just had a look at mine and put 'em in on TOP of the bottom (rebound) spring, still no evidence of #67-4131; seems to ride fairly nice
That's the best I can do for now, so let's hope the rest of the jury don't lunch too long