Yes, it's possible, but if you normally build using a solera, then it requires a different construction technique. Some makers have a join between the neck and the extension part (under the fingerboard above the 12th fret), which makes things a bit easier, but it's better practice to have the neck extend as a continuous piece right up to the soundhole. For the ones I've made, I decided it was better not to use the solera method, and built the body and neck separately, and used a tapered tenon to join them. That joint is tricky to get right, as you're trying to control the neck angle in 2 axes, and also get a perfect fit in the tenon itself, and between the heel and the ribs, and between the fingerboard extension and the soundboard. I wouldn't recommend attempting it until you have built a good number of traditional guitars.
James Lister, luthier, Sheffield UK