There is no way to check for for continuity in Maya using polygons. There are crude tools in maya Nurbs for fillets, rounds, and sewing surfaces, the square tool, and project tangency tool where you can specify tangential constraints (G2).

You can estimate G3 by eye but judging rate of change of curvature without comb plots and other continuity tools is impossible.

G2 curvature is easier to achieve by simply building the poly cage on top of a nurbs surface. But then when you cut the surface to create a seam you have to once again just play it by feel when placing the supporting edges on either side of the seam as the overall surface curvature will change when you cut it. I always have to re-snap the verts to the nurbs surface and then manually make small adjustments to maintain Tangency and overall surface curvature along the seam (and once again this is all very much by eye).

G1 is trivial and is the only form of continuity that does not require any additional tools to verify and so all you can really say with certainty of any two surfaces that meet at an edge in maya is they are always at least G1.

You can get a very good approximation of G2 and using a chrome environmental shader you can get a similar visual check as with a chrome shader in an actual surfacing application. But once again there is no zebra shader or comb plot with Maya so it's all touchy feely.

NOTE: The above applies to trying to capture Nurbs surface continuity when converting to polygons. Maya does have crude and I mean very crude Nurbs tools to create fillets and rounds and sew surfaces with G2 continuity with tangential constraints.

NOTE: read up on Nurbs surfacing tools. - specifically....

- project tangent (pick a curve and a surface) as far as I recall this is the only tool that you can specify curvature (G3) continuity in maya.
- square tool This tools options can specify tangency and the tool will actual display if tangency is achieved
- and of course the fillet, rounds, and stitching tools

Correction: I have been using Cx notation. The correct Gx notation for positional, tangential, and curvature continuity is G0, G1, G2 respectively. The x value implies the degree of the differentiation of the vectors tangent to the common edge between two surfaces. So just subtract 1 from all the Gx references above. Sorry.