Single Trigger Question

[Mike of the Mountain]

I have two Parkers with a single selective trigger and both work exceptionally well. First one is my two barrel set 20g Trojan (straight stock, checkered butt) and the second is my VHE Live Bird gun. Both have the same location for the selector which is a lever in front of the single trigger. You move it left to select the left barrel first or right to select the right barrel first. The Trojan has a toggle type mechanism and the VHE has a lever. I had two professional double gunsmiths look at them and both said they are of the Miller style. Neither have "Miller" stamped on the trigger though and both letter as single trigger guns.
First two pics are the Trojan toggle, second two are the VHE lever.