yo daddyo,
here is a list for you:
2SC2312= final. can be substituted for the 2SC1969 and the 2SC1307. these are not made anymore, and most of the ones you find online are fakes. they are a great final, very robust, and will usually put out a watt or two more than a 1969.
2SC1307=final. can be substituted for the 2SC1969, and the 2SC2312. these are made of unobtanium and will not be found anywhere except inside an old 70's SSB cb. great final. again, if you find any online for sale, they are probably fake.
2SC1817=final. can be substituted for the 2SC1969, 2SC1307, and the 2SC2312. these were not used in too many radios, and have not been made in decades. good final, and usually puts out a watt or so less than its counterparts. you MIGHT find someone selling a NOS one of these, as they are not as well known. there are probably fakes being made of this one too.
2SC2166=driver. This was also used as a final in some AM cb radios in the 70's. great driver, and matches up well with any of the finals listed above. these can still be found online sometimes, but are still very rare. yes, there are fakes.
2SC2314=driver. very good driver and tends to push a few more watts out of the 1969 and its counterparts. this is the driver of choice when modding 25 and 29LTDs. not a drop in replacement for SSB gear.
2SC1957=driver. also a good driver, but doesn't put out quite as much as the 2314.
good for a driver in AM units like the 25 and 29, but is not a drop in replacement for SSB gear.
As Robb said, the IRF520 MOSFET is the go to replacement for AM radios these days for both driver and final, and gives a nice power boost to those radios.
it is also used in SSB gear, but they are not drop in replacements for radios with SSB unless the radio already came with them from the factory.
you will find instructions to do the change over in the older SSB radios, but they can be a pain in the butt to get right, so not usually recommended for the casual modder.
exit13 has posted great tutorials for using these mosfets in the older mb8719, and upd858 radios, but again, there is still the possibility of part value tweaking required.
no two radios are ever exactly the same.
You will find in your reading that Lou recommends some motorola drivers and finals as replacements, and they do work, but they won't deliver any more power than the stock transistors. those MRF transistors are also not made anymore and will be expensive.
as for the price of the repair, it could be a LITTLE bit high, but depending on how much troubleshooting was involved, it could also be a sweet deal.
repair prices are almost never based on how many parts are replaced, unless they are very rare, or in a case such as replacing all the electrolytic capacitors in an old radio.
it's the troubleshooting that you are paying for. who knows, some other guy may have found the bad regulator, replaced it and called it good. they may have charged less, but from the sound of it, the radio would have been back at the shop before too long.
the scope is imperative, but if it were me, i would start with a good watt meter, a good RF signal generator with a calibrated output level, and a good accurate voltmeter, both digital and analog. try to find voltmeters that will measure AC millivolts.
find the instructions online to build your own dummy load, because tuning other peoples' radios with your antenna can cause some confusing results sometimes.
you really want to know that you are tuning a radio to a load with no reactance and a true 50 ohm value no matter what frequency you are on.
that first chapter in the Understanding and Repairing book where Lou shows you what kinds of equipment you should have, and how to make some of it is pure gold.
follow what he says there.
hope this helps,
LC