No, YOU unlock the clarifier, as a part of the installation procedure.
Bear in mind that if you install the tiny RF choke in line with one leg of the varactor diode the way they show it, you will probably see some schizoid behavior from the clarifier.
Putting that choke in that spot works for similar radios, like a 148, or a Madison, or 2000GTL or Grant XL/LT, but they have a different clarifier circuit in the first place. Placing the choke in line with the tiny varactor diode does NOT work the way they say in a 142.
If you can live without trying to make the clarifier slide a whole channel, leave the choke coil out.
If you feel you MUST stretch the clarifier coverage, placing the choke in line with one of the two wires from the kit works a lot better. Still makes it harder to get the radio back onto the center of the channel.
Another detail they forget to mention is to split the two 'married' wires leading from the kit to the circuit board. Separating them by about an inch tends to make it easier to get the radio back onto the center of the channel.
Gave some thought to working up a 'revised' procedure for the EXPO "B" kit, and then they got discontinued. Hard to work up any enthusiasm for it now.
About that "limited knowledge" thing. If everything falls into place easily, and tunes up the first time, you're fine. And if any part of it ends up being "close", but not close enough, that's when the experience and tools make a difference. One good thing about the EXPO kit is that you can put the old crystal back where it was if things don't work out.
73