Yes, so far as I know the 5500s contained the same 1520 / 1530 calibre movements.

Yes the Explorer dial has often been put in an AirKing 5500 in order to render it more valuable. There is often no way of telling what is real except by sending it to Rolex themselves who can often establish from the serial number what the watch was originally produced as. How well do you trust the seller of the watch???

I myself have a boxed 5500 Explorer among my collection. There were a number of variants, some with gilt dial, some with white, some marked Precision and some marked Superprecision.

Kind regards,