Early smallblock motor mounts.

Hey guys. Another question.
Are the early (1964) 273 motor mounts different from the later ones. The originals have one large stud going through them with a large nut on either end. The new ones I got from Rock Auto are smaller and have a stud on one side and two studs on the other and are slightly offset. Not sure what to do here lol.
Thanks for any help.
Wally.