MIMF

I have an older Guild Acoustic guitar, that I've always enjoyed playing, but it's neck has always felt sticky.

10 Years ago or so, I took it in for repair: He buffed out the neck, leaving two spots with no finish and a much worse feeling finish on the neck. I have to work the neck with a cloth before playing and after a few songs to make it feel good to me. Havent had to do this with any other instrument.

I am relatively inexperianced in finish/repairs: I have built one acoustic guitar. It has French polished shellac finish on the body and a Tru-Oiled neck. Love the feel of the Tru-Oiled neck.
I was thinking about just sanding/scraping off all the finish and applying a Tru-Oil finish to the neck.
Can I just finish the areas that bother me and leave the heal/headstock alone? I imagine I would need to use shellac rather than Tru-Oil if I go that route.
Note: I am not at all worried about the cosmetics.

I do not have acess to spray equipment.
How do you suggest I fix this?

The lacquer on that neck has gone gummy. This happens a lot on the old Guilds and Gibsons. I have found no way to get that to go away! You can probably scrape or sand the finish away on the shaft and leave it on the peghead and maybe the heel, but you'll have the transition to deal with. I've seen it done and it can look good enough, but it certainly feels a whole lot better.

You could treat it like violins and remove finish as you say with headstock and heel and then use tru oil. It won't look great but if this is your working guitar it's the sound and feel you are after. I've seen instructions online to do something similar to what you are trying to do to perfectly decent finishes just to get a "faster" neck. I'm not sure it does that but you can always tell people it's that way to improve tone and speed

I was actually thinking the same thing. I have the neck scraped down except for the heel and head. It looks very much like a violin. I think I will use Tru-Oil, and no pigment, and just let it look like a violin.
Will I need to seal with shellac? I imagine the Tru Oil/lacquer transition will work better that way?

I've done this, and I was quite happy with just a few coats of shellac. That feels great to me.

Tru-Oil does not need a sealer.

Shellac is the better choice for the finish in such cases. Oil finish easily can become gummy if applied too heavily, but shellac will dry harder and have less friction. It must be kept very thin, just enough to seal the wood. I have used many finishes on necks over the years and my favorite is Behlen's Rock Hard Tabletop Varnish, which has now been changed to something other than what I originally liked. Shellac is my second choice. You might do well with the Tru-Oil if you use it with 800 grit sandpaper and wipe the neck dry immediately afterwards. Less is more in this case.