I'm sorry because I don't think my answer helps to remove doubts but I believe that every choice would be right, that is, in any case it is not wrong,
lyou forgot the signature and date, so you can add it now the date with old name,
but it is also correct to put the date of 15 years ago, the date of the period but the current name, perhaps writing a work of, carried out in the year, around the year .........
that is, in my opinion it is as you prefer, if you want to sell them under the current name, so that from this year on you only use the name of now, so that you will no longer have to go back to using the name of that time for any work you can do it, so you use current name here too, that's right
or third option, if you want to use the current name but adding a clarification, you can sign with your name saying that these drawings were made on the date of, in 2006 and that then the artist was recognized with the name ...
maybe this in a note, a sheet to print and add to the work, or you write it on the back, or a kind of stamp on the back, or a separate note, I don't know. in order not to sign too long I say, but okay well write: 'current name BEFORE previous name'
for me the most correct is the choice you think you prefer, because none are wrong.
if what is written is stupid, I apologize. I am however sure that they will be able to tell you better and that both things are right and that you should choose the choice you prefer
