Could be rootstock

In other words if your tree was a grafted cloned variety the suckers will be from the roots of the "generic" version and different from what you were growing.

If I were not sure and it was an important spot I would start over. If it were in back and I was interested in seeing what creature I had I might let it go.

From the diameter, I'd say the chances are exceedingly good it was grafted.

If they are scion rather than rootstock they should bloom in a year or so and then you will know.

its obviously viable .... it growing ..

what they suggest.. is that it might not be a valuable fruit ...

you might want to check in in the fruit forum or tropical fruit forums.. or the citrus forum if there is one ... in one of those places you might actually find a lemon freak who will know the answer ...

ken