The Bf 109 G-14/AS came in two "flavors"... there was a first version (which I define as "early") with no chin bumps and which was mostly built by Erla (462xxx batch), the bulk of the G-14/AS production however, was built at Regensburg until late February 1945 (78xxxx batches) and - probably for production issues and the need to uniform parts, apparently most of it was completed with the lower nose cowling of the same "chin bumped" type of the K-4 version, which BTW was built together with it on the same production lines.
Apart from uniformation of production, there was no technical reason for the chin bumps on the G-14/AS, as this sub-type did not have the water return line protuding outside the cowl outline which made those bumps necessary on the G-10 (the Erla version had the cowl redesigned to dispense with them) and the K-4.
Thus, the exterior aspect of a G-14/AS built at Regensburg could be quite identical to a G-10 built by WNF, apart from the oil filler hatch on the nose (higher on the G-10/K-4 and lower on the G-14/AS) and the round "cold weather start device" hatch on starboard side of the upper cowl which on the G-14/AS was in lower position, while on the G-10 and K-4 was in higher position.
The book of Prien/Rodeike, while is to be praised for its importance, on this issue and on the "G-10/AS" (a version which has been proved non-existent, the confusion being caused by the complete redesign of the nose section of all the G-10s produced by Erla) has become obsolete, thanks to the steps ahead made by researchers since its publication.
Sorry to have tried to condense complicate and conflicting infos into a reply of a few lines. Hope to have been of some help, though.
P.S. Further details can be found in this old discussion thread which is still up at:
http://disc.server.com/discussion.cgi?id=154196;article=6477;search_term= D'Amico;show_parent=1 and
http://disc.server.com/discussion.cg...;show_parent=1