61.75 Private pilot certificate issued on the basis of a foreign pilot license.
(a) General.
(b) Certificate issued.
.... A person who holds a foreign pilot license issued by a contracting
State to the Convention on International Civil Aviation may be issued a
U.S. private pilot certificate based on the foreign pilot license without any
further showing of proficiency, provided the applicant:
(1) Meets the requirements of this section;
(2) Holds a foreign pilot license,...
(3) Does not hold a U.S. pilot certificate other than a U.S. student pilot
certificate;
It doesn't say "does not hold a FAA without this rating." And you can go the other way, have the 61.75 and then later get a regular FAA cert and still keep the 61.75.