He may be lower sleep needs, yes - certainly possible! I'm assuming he sleeps well nights and naps and seems happy in A time? At this sort of age my DD was on around 3.5h A time, but would typically do one longer and one shorter nap with a longer night. Total sleep time was probably similar overall to you DS, it was just distributed differently (more like 1.5-2h in the day and 11.5-12h at night).
So yes, you may need to start shortening one nap if the shorter night is not working for you all. You can choose which one - and bear in mind when you cap a nap, the following A time is usually reduced too. We kept a long morning nap and had a shorter pm nap, so the A time before bed was quite short - around 2-2.5h once we got closer to 4h A time with 1x 1.5h nap and 1x40-45 mins. With an EWer the usual advice is to shorten the morning nap from the front end, so instead of 9.30-11 you might do 9.45-11, or 10-11, and might have to move the afternoon sleep a little earlier to compensate x