This strikes me as a no brainer. Cyberverse, WFC, and Studio Series have all used 3mm and 5mm translucent blast effects. There have been a ton of weapons and accessories using LEDs, some smaller than a Transformers' head and a battery compartment barely bigger than a watch battery. Including weapons with built in LEDs. 3mm is even a standard LED size. What I haven't seen are generic rifles you can plug translucent blast effects into with a 3mm plug and/or a 5mm port. Preferably with a 5mm handle. But it's a big fandom. Lots of 3Ps out there. Maybe I missed it. Maybe there's something with an unintended use. I'm pretty sure there are LED kits you can plug into Prime Master hands/feet and I've never seen anyone actually do that before so maybe it's a thing I missed.
Personally I would rather have effect part packs with original battlemasters. Light up features are completely inconvenient. They're neat when you are messing with a figure and taking photos, but for display purposes they suck to turn off and on. Specifically for what you are asking for - there exist some LED guns/accessories for specific figures that have popped up over the years. I highly doubt they are compatible with siege era effect parts though.