M58653P replacement for ER1400

[MilanMilosevic]

I have found this EAROM from Mitsubishi: M58653P. It looks like a direct replacement for ER1400. It is also an old IC but can still be found at dealers and on websites. Not expensive (cca 8 EUR in Serbia) so would be OK to make a little stock of it. It has the same pinout as ER1400, the optimal Vcc is specified at 30V (but the operation range is up to 40V, therefore +33V is OK). The only difference is that it has half the memory (50 words x 14 bits) of ER1400 (100 words x 14 bits). Would this half capacity still be sufficient to store all the data from 20 stations? I cannot figure out how B261 uses memory words to store frequency and characters.