Someone seems to have spotted this already
Like I said above the information is publicly available in the Observation Scenario. You can check the Sentinel-1 Acquisition Segments and see if there were acquisitions over your area of interest.
Basically what I am trying to say is that for S1-SAR you need to look at this from a different perspective - the point is not if there are gaps, the point is if there were even data acquisitions over an area of interest during the time of interest.
You can also consider to contact the official Sentinel support. and ask this question. Note that this forum is for the SNAP software and related Toolboxes, so don’t expect to find many users who are able to reply to questions about the acquisition scenario.