Ask what the Imax and Pmax is. The maximum current under full load, the voltage under load and the fuse size. It would be nice to get the Mfg name and model number. That way you could download the specification sheet off the internet.
If there are not enough panels to complete a string, then voltage matching under load must agree with what you can buy to finish.
I just saw where they have hundreds of them. Get enough to complete the loading on a 60A charge controller. Either 9 or 12 panels on a 60A - 150 VDC charge controller. That would be 3 strings of 3 or 4 strings of 3 to get a full load on the charge controller.
