Y'know, I never really gave the builder's plates much thought.
It looks like the changeover from the rectangular builder's plate to the oval one occurred sometime during the F3/E7 production (1945-1949.) I couldn't locate exactly when the change happened, I'm sure someone out there knows. I'm guessing around 1947, because the Train of Tomorrow and Texas Special E7's were built in that year, the T.S. E7's have the rectangular plate, the T.o.T. E7 has the oval.
Here's the beloved UP 1402 again:
Notice it bears the rectangular plate (Heavens! Another ding on the faithful SHS model .) Also notice the "A" has been patched out...
Meanwhile, here the 1441 is bearing the oval builder's plate.
Either way, I'm not gonna worry and get all nit-picky about it. I've decided one can go nuts thinking about such things.
I'm going to stop thinking now...
(BTW, notice the 1441 also has the "passenger" pilot...)
Rusty