What is also relevant is that there was no DRB/1 silencer reference until after Ann Eaton handed a sound moderator and all the other bits and pieces over to police, on 11th September 1985, under AE, CAE and then DRB references...
The sound moderator sent to the lab' on 13th August 1985, had the identifying mark SBJ/1, lab' item no. 22, and was clearly a completely different sound moderator to the one which Ann Eaton handed to police (AE/1, CAE/1, DRB/1) on 11th September 1985, which was not sent to the lab' to be checked for blood and fibers, until 20th September 1985...
Incidentally, 'Ron' Cook, the (SOC) fingerprint expert, checked silencer SBJ/1 for fingerprints on 15th August 1985, by reliance on the oblique light technique, and again on, the 23rd August 1985, by super glue technique, whereas, DS Davidson and DS Eastwood, fingerprinted the silencer (DRB/1) on the 13th September 1985, handed into police by Ann Eaton on 11th September 1985...
For the benefit of doubt, it should be pointed out that once 'Ron' Cook had used the super glue technique to fingerprint the sound moderator (SBJ/1) on 23rd August 1985, it would be hardly worth re-fingerprinting the same sound moderator(DRB/1), again, on 13th September 1985, by Davidson and Eastwood, now would it...
Since, Davidson and Eastwood, are both still very much alive, the most obvious questions to ask them would be, (1) - "what was the exhibit reference to the sound moderator you fingerprinted on the 13th September 1985? (2) - were there any signatures present on the exhibit label prior to handling it? (3) - Do you know how it came to be in police possession at that stage? (4) - What did you physically do with it, once you had fingerprinted it? (5) - Did you find any fingerprints upon it when you examined it on 13th September 1985? (6) - Did you obtain any fingerprints for elimination purposes at that stage? (7) - What date was the silencer you fingerprinted on that date, sent to the lab', and who was it received at the lab' by?