For you Henning nickel aficionados I came across a post on a metal detecting forum where the poster is showing images of a 1945 with
P over the dome.
Quote:... "Well, this one is a 1945 with
no mint mark above the dome, which also has the same worn look as all of Henning's other nickels. And though there are no other markers I can find, no "EN" mark or looped R in PLURIBUS or reverse die break, it does have a small dot above the dome at about 1 o'clock (dots being indicative of counterfeit coins) and weighs in at just 4.83 grams."...
There is an obverse image of a 1945 nickel and a war-nickel looking reverse image with no P over the dome.