Wow! That is one
honest seller!
Look closely at the plate structure of the tube you linked, and where the pins transition through the glass base.
Compare to the known Mullard EF86

And to the known Russian EF86

Also consider the markings on the tube you posted; at the time RCA was using the block-logo, it was almost always red, not the white that was used on that tube. And Mullards always say "Made in Gt. Britain" and not "Made in
England". I've come across other Russian tubes with that white print, claiming to be Brimar and with the wrong details to the labels.
I've also had Russian 6P3S (6L6-like) tubes with an RCA label in a box with RCA markings where the tube was labeled "Made in Germany." However, 1) to my knowledge German companies didn't make a 6L6, and 2) the plate structure and style of getter and bulb clearly gave away the tubes I had as being falsely-labeled and boxed Russian tubes (I didn't know the details to look for when I bought them; this was mid-90's timeframe).
The most plausible explanation I heard was that early fake-labeled tubes weren't intended to deceive in order to cash in on the "NOS craze" (because it hadn't happened yet), but were imported prior to the fall of the Soviet Union and were intended to side-step import restrictions. Until the mid-90's there was still a T.V. repair shop in the city I lived, where I could buy all the authentic RCA tubes I wanted for a fraction of what a music store charged for new-production Russian and East European tubes.