Polypterus bichir bichir and bichir lapradei has both been classified as Polypterus bichir for a few years now. (I think at the same time when they reclassified Polypterus palmas)
I'm not 100% sure on location of Tinkisso river but I believe Toyin told me or I saw several years ago, that those 2 "variants" are considered the same thing. Tinkisso river used to be a common selling point from Guinea 10+ years ago but it vanished and now you see "Dabola" endlicheri instead. They also do look the same if you look for "tinkisso guinea"(sometimes typed as tikinso) endli photos from 10+ years ago and compare to the "Dabola" endlicheri now days. Although, now days I do sometimes see "tinkisso" bichirs being offered (it will sound new and enticing to people who have never heard of it before).
But honestly some of the more "specific" location (ie: tinkisso river, milo river, sankarani river, dabola, faranah, etc) don't matter too much in my opinion. As all those I listed could just be considered "Guinea" since they are all in Guinea, so arguably they are all the same thing. I think all the "specific" location mainly is just a marketing tactic from the African exporter/fishermen. I think Nigeria has lately started to do the same. We used to label as endli/laps from Nigeria as Polypterus endlicheri/bichir "Nigeria". Super general right? But in recent years, I'm starting to see Nigerian fish marketed with more specific names such as "Ogun", "Benue", "Nasarawa", "Bayesla"/"Ughelli"(I think these 2 are same location/area), etc. African exporters are learning that hobbyist want to collect "different"/"new" locations. That's just my 2 cents anyway since I generally don't see a significant difference amongst those "different specific" location within the same country. Don't get me wrong, there is definitely some differences amongst like P. bichir "Nigeria", P. bichir "Guinea", P. bichir "Chad", and P. bichir "Kenya".
I always advise people, don't buy the fish because of it's name/location. Buy it because you like how that specific fish looks.
sidenote: I believe Corubal river is the same thing as Koliba and Koulountou river is Koloton