Can anyone tell me what the original fuel tanks on a 79 Scarab (miami vice) are made of. The ones I'm looking at look like fiberglass to me but the seller says they are glassed over aluminum. Is this kosher ?

I have a 78 in project and it 155 gal alum. It may look like glass but if you look und the back seat it should have a tag by the pick up tubes. miami boat didnt come out till the 80's. Would love to share some pics with ya though