Its not as simple as "drop in and go". It depends on how the bolt was milled.
Some bolts were left as semi bolts so it required altering the trip/disconnect in the lower. The problem with that is is considered a conversion (not a very reliable one) so the bolt could not be removed from the host without replacing the disconnect each time. (A royal PITA)
The ideal bolt is milled to clear the disconnect and is truly a "drop in" affair. Many bolts were later slotted for this reason. Caution must be exercised as the Rockwell was high on some of them requiring carbide and plenty of coolant. Annealing is an option but I've seen them distort when retreating, especially the Catco bolts.
The issues were caused by sloppy guidelines from ATF as to what was a MG after the initial 1982 KG-9 ruling. While some semi open bolts were seized as contraband, no formal ruling was ever issued and occasionally they still show up for sale as "KG-9 replacements". It gets murkier as the Interdynamics changed the bolt handle slot position when they redesigned it into a closed bolt KG-99. This was done to prevent converting one back to an open bolt simply via replacement. Many of the aftermarket bolts sold had TWO bolt handle slots so they fit both KG-9 and 99 uppers. Possession of a dual slotted bolt and a KG-99/TEC-9 could easily be construed as illegal even if the bolt was still in semi status (unmilled).
Regardless, the biggest issue is getting ANY bolt to run. While seemingly simplistic, there are many parameters that inhibit reliability with this design. They can all be made to run eventually, but be prepared for a LOT of tweaking. Ideally, purchase a bolt AND a host that the seller guarantees already runs.