Your Horse van is a beauty.
It was advertised in the 1952 U.S. catalogue but with a mistake. The word "EXPRESS" above the windscreen is correct but the side shows "EXPRESS HORSE BOX" instead of "EXPRESS HORSE VAN".
The factory drawing 13 500 A shows the position of the transfer and stereos for this american issue. There is only one transfer, it is the "EXPRESS" above the wind screen. All other markings are by tampoo.
Stereo probably means rubber stamp in Meccano language.
The 980 can be fitted with either red or maroon hubs of the same colour as the body.
I have not yet seen a box blue or striped printed with Dinky Supertoys. The boxes for the 981 British Rail and 979 Newmarket was printed with Supertoys. Was the marque SUPERTOYS registered in the States ?