Ammeter Bypass a Must?

"From where I sit"

1...There are issues with "restoration correct." If you are past all that, then no issue
2...All of this depends on the conditions the vehicle experiences, AKA corrosion, humidity, "rust belt" etc, the amount of current, IE accessories, pumps, fans etc
3...As mentioned "mostly" the BIG issue is the bulkhead connector. "One way" around that is to snake larger wires directly through the drilled-out bulkhead connector cavities.
4....Ammeters vary over the years. One big issue (as my 70RR Ralley dash) was the ammeter in some vehicles is bolted through the PLASTIC housing, so if "anything" gets warm, the plastic softens, the connections get more loose and worsen, and you have a rolling snowball........in this case a fireball

Other clusters use a metal cluster and insulating washers. These types clusters are a little better. Another ammeter issue is that the studs are not fastened to the internal shunt. You can "gain a lot" here by soldering or low temp silver soldering the studs to the shunt. Now if you get the nuts tight "as in jambed" you will avoid some ammeter issues
5....Likely one of the better ways to go--and most time consuming---would be to convert in some way to an external shunt meter. The C barge cars did this as far back as 71 or 72 I don't remember. This uses a sensitive meter (small wires) which go out into the engine bay and "tap in" to the harness itself and use the voltage drop in the harness to indicate on the meter. One problem with external shunt setups (notably Ford trucks and Rangers) is that they tend to be "numb" that is the needle hardly moves when you turn on the lights at rest

6...As others have mentioned IF everything is absolutely up to snuff, IF yo have NO high current accessories and IF you have nothing larger than "say" about a 45A alternator, the OEM system will likely "do ok."