They aren't Fake.
Plucots are 75% plum and 25% Apricot...and
Apriums are the reverse, 75% Apricot and 25% Plum. These are the result of hybridization, not a grafted or mutated line. Zaiger Genetics in Modesto,CA developed both strains and holds a trademark for APRIUM. He markets them thru many nursery wholesalers. For me that means Stark Brothers in Missouri.
We had 2 Apriums and 5 Apricots, and 2 Plucots with 2 Santa Rosa plums in our little orchard on the High Desert of SoCal. They were in their 10th season when we left.
The Aprium looks like a large Apricot. It tends to be a bit earlier than most Apricots, which caused some loss to frost there on the desert. (4000' elevation). It has a reddish tinge to the inner golden 'meat' of the fruit and is very sweet, even when not quite ripe.
The Plucots didn't fair as well, and seemed to be a bit less hardy in the desert climate (drip-irrigation for all trees required). They looked like their Plum cousins (dark smooth blue-purple skin) the inside had the yellow tinged pulp one sees in a Green Gauge(sp?)Plum. They tasted like a Plum-Apricot mix, where the Aprium was more a sweeter Apricot.
We do not have an Aprium here in Indiana as the frost is to late in the season for the fruit to survive. I wish we did. We got tons of great fruit from those trees and made all kinds of neat preserves with it.
Jungle Jims has the Pluots quite often, but I haven't tried them.