The Messenger of Allah ﷺ said, "Name yourselves after me, but do not take my kunya. I am Abu Qasim."
حدثنا عبد الرزاق أخبرنا داود بن قيس عن موسى بن يسار
قال رسول الله ﷺ تسموا بي ولا تكنوا بكنيتي أنا أبو القاسم
Its isnad is sahih. This has already appeared at 7371, 7372, 7523, and 7641 with the wording, "Take my name, but do not take my kunya." In this narration there is an addition, "I am Abu Qasim."The wording we have established here is what is fixed in K, and it is supported by what appears in M, though that version is corrupted and altered, for it reads, "wa la takunun," which clearly shows that the original was "takunu," meaning the copyist made an error.In H it reads, "Take my name, but do not take my kunya," and in Jami al-Masanid 7:384 it reads, "Take my name, but do not take my kunya."It seems to me that this is an alteration by the copyist, who perhaps wrote from memory, so he wrote the wording that is more commonly repeated in the narrations and that comes to mind first.