the Panama 1¼ centesimos (KM# 15, Panama "SCWC" number for the planchet) is 20mm diameter and 1.15 thickness.
the Lincoln cent is 19.1mm diameter and 1.52mm thickness. (KM# 132, US "SCWC" number for the planchet)
Both weigh 3.1g.
Now, the Panama 1¼ centesimos was actually struck on Lincoln cent planchets, absolutely no difference as far as the planchet goes before the strike, the same stock was used for both coins, 3.1g weight, the difference between the two lies in the diameter and thickness due to the collar used.
Now the 1941 wrong planchet example that exists and graded by PCGS
was stamped on a 2 1/2 centesimos (KM# 16 Panama) which is a different composition and weight. It was copper nickel.
The 2 1/2 centesimos had 3.3 grams and a diameter of 18 mm, and it was slabbed with incorrect info on the label, it's not a panama 1C planchet
there would be no difference between a Lincoln cent KM# 132 on a KM# 15 planchet, because its the correct planchet for the Lincoln Wheat cent
and used by the US mint for both coins when they stuck both of them.
The error coin is on a KM#16 planchet. If you look at "1941 Lincoln Cent Struck on a Panama 1C Planchet -- MS65 PCGS
" you will see pictures of the slab. it was labelled wrongly as "stk on Panama 1C plan",
This coin is the copper nickel Panama 2-1/2 Centesimos KM# 16 planchet, clearly evidenced by it's color.
I've gone down this rabbit hole myself and done the research to come to this conclusion already, feel free to look into it yourself independently.
What you have is an underweight Lincoln Wheat cent
. Probably at the low end of the tolerance, and then wear I think, for sure it's not a wrong planchet or an off metal.
I also don't have one of them 1941 off metal Lincoln cent on panama planchets.