Can I use membership cards with RMS?

If you simply want the ability to scan a membership card to lookup a customer on file, yes.
Purchase barcoded cards or fobs that show a serialized number starting at a higher number than any of your current customer accounts. 
Example, if your current customer accounts are 7 digits long, start with 8 digits for the membership cards so there is no overlap, such as starting number 10000000.
To add membership card lookup to an existing customer, locate that customer, view properties, cursor to the account number field, then scan in the card you want to assign.
To add a membership card to a new customer, scan the card into the account number field as you are creating the customer.

Note: V.I.P. Zone defaults to auto-generate customer account codes. If you want ability to manually create account codes or scan in membership cards as above, select the Setup tab in V.I.P. Zone and disable auto-generate under the New Customer frame.

If you want tracking capablity such as loyalty points on sales to members, that would require an add-in.