Wrenches....

I've been trying to collect a full toolkit for each of my Cat's
(D2 5J, D4 7J, D7 7M) as listed in the parts books.

I've found open ended wrenches with the relevant CAT part numbers (5B78x) made by Armstrong (by far the most common), Billings, and TS & S (The latter seems especially unusual).
I'm wondering why three suppliers (rather than just one) unless of course there were more than three ?
Does anyone know if these manufacturers are still in business ?
I've also got an Armstrong wrench size 1 x 7/8 with part No. A-1733, does anyone know for which equipment (or during which years) this would have been supplied ? I guess it must be later than the mid 40's.

Thanks.