The seller on ebay gets the cabinets then restocks them with vintage NOS Xacto pieces.
I think the last year Xacto offered this set, the 3-panel larger #99, and the smaller #88N Hobby Den was somewhere around 1981.

The #89 set pictured here was the 2nd largest set offered by Xacto.

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When in doubt, WHACK the GAS and DITCH the brake !!!

Yes, there is such a thing as NORMAL, if you have to ask what is "NORMAL" , you probably aren't !
Failure may not be an OPTION, but it is ALWAYS a POSSIBILITY.
ALL systems are GO for MAYHEM, CHAOS, TURMOIL, FIASCOS, and HAVOC !