That is one of the last XXXs -- note the LX-style blue leatherette covering on the top. If it was a rebuilt machine it would have a tag on it indicating as such.

The very last version of the XXX also had the bright blue-green undercarriage paint of the LX as well, but this one would still be worth saving because it was manufactured in far lesser quantities than the most commonly found 1949-52 version.

I'd take it if I didn't still have XXXs coming out my ears!

If you want to see the numerous variations on the XXX, see my link.