Yes, this should be possible. However, it is recommended to use two RAM modules of the same type. Unfortunately, adding a matching module is not as easy in this case, as the pre-installed OEM module is not sold separately.
You can check with cpu-z to see if there's a free slot, but overall yes, you can put two 32 GB ram bars of the same frequency, I'm currently using kingston fury ddr4-so dimm bars.