Later model bucket seats in early A's
the floors will need new holes drilled for buckets.
I replaced the carpet in my Signet this spring,
there were 4 old holes with "seam sealer" putty in them,
in the spots a Bench seat would have been.
It seems the body came with the holes predrilled/stamped for a bench seat.
Use whatever you like, the Signet buckets are Very wide.