Need help for this Mammillaria

I purchased this Mammillaria on ebay (Named Mammillaria Rep 1308) yes you guessed it, wrong field number, so i am asking for a little help to clear the air.
When checking the field numbers i came up with (Pilosocerus polygonus Rep 1308) even i know the difference between the two plants.
 
https://servimg.com/view/16421531/21
https://servimg.com/view/16421531/22
https://servimg.com/view/16421531/23
https://servimg.com/view/16421531/24

Looking at the photos, I thought that it was either Mammillaria wagneriana or pettersonii.
I then checked the Reppenhagen field list, and searched for wagneriana, and lo and behold - Rep 1508, wagneriana - from Rancho de los Landas, 1900 m, Jal.
So just a slip of the pen, it would seem.
Its a very nice long spined form indeed!

Thank you for that Chris,
i am very happy to hear that you could id that Mammillaria, this is one that i did not have.
So buying on ebay can have an upside, even if the field numbers can be mix up, once again thank you very much.
Rgards:) Arthur