Ed, there were several adjustment tools that were used for various ferrite cores. The next answer is "yes" on CO DTMF receivers, but "seldom" on later-era subscriber equipment.

The 247A dial intercom adapter was notorious for not being tuned in properly from the factory (you probably recall the tedious BSP instructions on how to get it to work even moderately well) and for going out of tune in the field. It was the first generation and was a "work in progress" to be diplomatic. The 247B was always spot-on out of the box.

I only saw and suffered from a couple of the A versions, and saw many B versions. Then they all were made obsolete by the packaged units from Teltone and Melco which were finally stocked by Bell companies who threw in the towel until the 4xx series of 8" intercom cards were brought out. They were the 407, 424, etc. and they never needed adjustment, either.

Arthur P. Bloom
"30 years of faithful service...15 years on hold"