Ohbebby
Thank you! Do you think such old questions would be still relevant?
There are very few of these in the OG2019 but about 100 of these have made it into the OG Verbal/Quant 2019.
Keep in mind that a meaningful number of OG 10 questions are in the GMAT prep, so you have a chance to ruin your score by working with these.
I would take Official questions based on the most recent to the oldest list. So start with OG2019 and go down to OG2016. It is very safe - you won't run into any GMAT Prep overlap. Once you step into the OG2015, you are starting to overlap.
These OG10 questions are much better than anything unofficial but you need to be careful when it comes to GMAT Prep overlap. Taking into consideration that many of them have been phased out from the OG2019, tells me that GMAC felt it needed to phase them out. As to why, I am still working on that part since I don't see anything wrong per se.