It is, shockingly so actually for ~1943-1945. Some is not published online, rather one needs to head to Podolsk to get to the really detailed materials. This is hard to do but very worth it. Those which work with these documents (both published online and not) know and can attests to their historical value. That is why over the past decade so many top historians are using them from around the world.
If one has reservations with using a Russian article for whatever reason, they can try a German book: Drei ""Falken"" der II./JG52 auf der Krim im Luftkampf um die Kertsch-Halbinsel (1943-1944). Looking at 13 II./JG 52 pilots the authors found the average victory-to-claim rate was 54%. If wishes to have another German historians opinion, Dr. Jens Wehner found the rate to be only ~56%. Our english book Verified Victories found the rate to be 58% on confirmed claims (listed in the OKL microfilms). This number drops when 1945 claims are examined as found in the pilot's logbooks/unit docuements (no OKL microfilms for 1945, unsure of OKL approved them). When small sample sizes are put to the side and the entire Luftwaffe is looked at for the whole of 1944 over the Eastern front, I found that the real victory rate was ~2/3rds. The overclaiming is squewed to certian units and certian individuals. Why that is the case will still take some time to uncover, certianly not because of dishonest intent as I found that less than 1% of claims could fall within this category. There is an ever increasing number of research over the past decade showing that certian individual's overclaimed at certian rates, this comes from multiple researchers/historians from different countries. Nearly all overclaiming is a result of failing to observe the enemy aircraft after making an attack, be that due to enemy pressure, weather, other factors.
It should come as no surprise that there is over claiming.
P.s. if one is skeptical of matching German claims to Soviet losses (most likely due to their personal unfamiliarity with these documents), they are welcome to review Allied documentation as well over the Eastern front. They will find a similar pattern, ex. the infamous May-8, 1945 claim, Duttmann's P-51 claim, etc. From renound French Historian Jean-Yves Lorant (author of the amazing JG 300 volumnes: over the west there could be a disparety of allied records and German claims of 1:8 when looking at fighter-to-fighter combats. Over claiming occured on all fronts.