Ron -
No they are not available to the general public, HK decided not to make a 10 round magazine for them.
I have seen P7M13's in Gun List and at gunshows, for about $1300 dollars new. Magazines are still seen on the gun show circuit, typically around $120.
No the P7M8 is not the same gun. The 8, and 13, refer to the magazine capacity. Otherwise they are identical guns mechanically. P7M8's are still available from HK, as is the P7 PSP. The P7 PSP is the original P7, and differs in that it has the magazine release on the heel of the grip. I have seen both the M8 and the PSP used for $800-900.
Hope this helps.
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