Hi Jerry !
I think this is the model George Barris promoted and Wester Auto sold and the predecessor to the dummys that has been repoped from then until current days . I never new the model number of those , no number on the box ? The 451 you are referring to commonly know as “baby Appletons” are not this model , see the Series 451 in Riks archive:
https://public.fotki.com/Rikster/11_car_photos/beautiful_custom_cars/great_custom_idears/appleton_-_lorainne/appleton_s-451/
There was also an earlier model of “baby Appletons” Series 141 , Riks archive :
https://public.fotki.com/Rikster/11_car_photos/beautiful_custom_cars/great_custom_idears/appleton_-_lorainne/appleton_s141/
Both these models have not such deep drawn housing as your Appletons . Ive seen some ad with George Barris and these Appltons but I cant find it now , got to be in the little mid fifties Rod&Custom or CarCraft magazines …
That’s about all I know , I think they are very rare , since Ive only seen maybe two sets for sale in the last 20 years , best of luck , hope they find their way to a mid fifties full custom !

I think Jim Seatons 55 Chevy had one of these set of Appletons installed:

OK here is a blurry pictures of the ad I was think of , I see these are the dummy spots George Barris promoted for CalCustom but the origin cant be any other then Appleton :

Wolf