The #5L handle is on page 21 of the 69-70 Xacto Catalog, only in the #92L and 95L Tool Sets. It does not appear as a separate item in the price list, so I assume it was only in the tool sets, unlike the #6L.
Just checked my three #5 knife handles; they all have the threads at the bottom of the collet and have the washer.
Did not check the #5 handles on my Hand-Drill and Coping Saw. They are on REALLY tight and I fear I would damage them trying to get them off the tools.

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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, and HAVOC !