I purchased the 1.0 versions of the Mist Hunter (G1-A Starfighter) and M12-L Kimogila Fighter that were on sale. Because I have the Scum and Villainy conversion kit I thought there would be no problem. However, when I located the base card for both ships they were medium sized. The ships and their bases are small sized. was there a mistake in the conversion kit for these ships or is there some way to put small ship pegs into medium bases?

It is not a mistake. Medium bases didn’t exist in First Edition, so some small-based and some large-based ships became medium-based ships. Your conversion kit should have included medium bases and some “conversion pegs” for small-based ships to be mounted on medium (and large) bases. The conversion pegs are cone-shaped.

Thanks! I found the bases and pegs.