We also purchased in 1993 a few days after Caskbill and also have an 8,000+ number for our first contract.
If you regard the last 6 digits, I believe the last five indicate the order of purchase at that resort and the 6th digit indicates the resort - with OKW as #1, VB as #2, HH as #3, BWV as #4, VWL as #5, BCV as #6, SSR as #7 and now AKV as #8. (I can confirm that #1 is OKW and #3 would be HH, but am not positive about the others).
Using this numbering system, if you had been the first to purchase a new contract (add-ons are a different issue) at OKW back in 1991, the last 6 digits of your member number would be 100001. The full number would be xxxxxx100001 . The contract number does have a suffix , usually in sequence from .001, .002, .003, etc.
If this is accurate the first to purchase a new contract at AKV would have a member number of xxxxxx800001. If you were #218, your membership number might be xxxxxx800218.
I'm not sure what the first 6 digits indicate in the member number - possibly when the purchase was made, the DVC guide and the phase of the moon at that time. ??????
Please report back if this is close - for any of the resorts.