Yeah that might do it, if not though, you can try;

Highlight your entire object, go to mesh-combine, then change the object to vertex view, highlight all vertex and go to edit mesh-merge vertex, change the distance number in the merge vertex attributes by clicking the little box to the right of the merge vertex option, the closer your vertex are together, the lower the distance number needs to be.

If its a case that you may of imported the object in from another program like zbrush specifically, make sure under export options, grps button is not active

See link for grp button;

https://docs.pixologic.com/wp-content...ool-Export.jpg

If this button is active it will export your objects in different polygroups resulting in objects not unified as one.