Rick,
Photos of McCudden's SE5a's have been mis-captioned in many of the more common Publications we have access to. Perhaps not "news" to you and Petrov but he flew two personal mounts while with 56 Sqn, B4863 and B4891. B4863 was the first one he had modified with the "bulged" cockpit, had a headrest, and carried the call letter "G". B4891 had a pronounced Bulged cockpit, no headrest, carried the same "G" letter, and eventually had the LVG red spinner added. The "G" was replaced by the number "6" when 56 Sqn. changed from letters to numbers on 29 Dec 1917.
Although the foregoing is pretty straight forward I had a heck of a time sorting it all out, between the Osprey titles (56 Squadron and SE5 Aces), the Datafile, and the Albatros Pubs SE5 / SE5a Squadrons books there are identical photos labeled as one or the other with the resulting confusion as to configuration and features. Also the style of radiator (cooling vane alignment) gets thrown in as well.
As for the Models, the Roden Kit as redone by Encore has the resin cockpit options for B4863. If, like I did, you choose to use the WNW Kit as the base for either of the tail numbers the resin cockpit enclosures don't fit. The solution is the Squadron True Details Conversion Set which works beautifully.
After all the angst I went through trying to sort out this issue I thought I'd give you a heads up on the possible pitfalls; my Build Log is over on the Aeroscale Vintage Aircraft Site, just search SE5a L. Carroll if you want further details.
Cheers,
Lance