I have this old pair of Technics SB-3130, they are three way speakers. Both of the super tweeters are dead (infinite resistance) and I’m not sure if this impact the range of frequency feeded to the tweeter. Given the schematic diagram, if I remove the super tweeter, should I modify something to have all the high frequencied on the tweeter?
If the STs are open, don't do anything. All the high frequencies are still going to the tweeter, it's just that they won't be reproduced as well as the ST could. You can probably compensate with the EQ at the signal source.
After further reading about filters I ended as the same conclusion as you. I first thought the L2 was removing high frequencies, but it is in fact an LC filter to remove bass more efficiently.