The Mark X made in Yugoslavia was marked 'Interarms/Alexandria Virginia/Zastavia Yugoslavia' on the left recv'r wall. Also had the ZCZ in a circle trade mark of Zastavia on the left wall.
'Mark X' was stamped on the left side of the recv'r ring of the action.

The Santa Barbara M98 action was made in Spain. But other than a very small 'SPAIN' marking on the side of the rear tang of the action,,there were no other markings or even proofs on these.
To see the 'SPAIN' marking you have to remove the action/bbl'd action from the stock.
The serial numbers on these generally begin w/a 'Z'.

Then there was the Centurion 98 mauser,,sold by Golden State Arms, Pasadena, Ca.
Also sold under Pasadena Arms Corp, Inc.
Seems to be the same action as the Santa Barbara,,no markings or proofs other than the small 'SPAIN' mark on the side of the tang.