No, it will not work well at all. Probalby has 1/4 its original charge capacity (they are Ni-Cd cells).
You can open it up and order replacement cells, install them, and have it working just like brand new.
I owned a Tek handheld oscilloscope for a while that had a totally ruined custom battery pack. I ordered 4 new sub-C NiCd cells (had to match chemistry because the charger was designed around them) and it worked great.