Not on the 109's PJ. The 20mm gun pods were factory built for them, but installed in the field.
It looks like you're correct. I've confused statements like the following (from the "Birds of Prey" site):
Unfortunately, the Bf 109 G-10 would usually reach the front line with factory-installed Ruestsatz armament kits.
with "factory-installed". It's not the same thing - and the variety of ruestsatz kits are truly bewildering. I also read an interview from an old Luftwaffe pilot, Franz Stigler, who said, in response to a question about the gondos:
"Oh, I never… I hated them!! I never had them on my airplane. As soon as I got a new airplane… I say, “That’s a damn part, off with them!”...Made it sluggish, you know. "
I took his "new airplane" to mean new with factory-installed gondos. As I admit, I have yet to see any evidence anything called a "kit" was installed at the werke.
So, valid correction...