cd keys: (rule is last group sum of digits mod 7 must =0)
sdk:	438-0973691		35
	438-1255877		35
	411-0555535		28
	438-5924125		28
	438-3653783		35
	438-1998807		42



other product id fields:
			all	x1	x2	x123	dif
262 254 001		22	20	16	12	4
451 052 001		18	14	13	13	0
318 056 080		31[20]	28	30	19	13(6)
048 056 011		25[14]	25	21	13	7
265 056 001		25[14]	23	19	12	7
437 056 001		26[15]	22	23	12	8(1)

310 051 051 ?		16	13	15	12	-2(5)