yes you can, this is usually a matter of replacing the driver.
On that middle light, I'd rule it out as filters will never work as well as a colored LED. A white LED which emits little in the red wavelength to begin with is going to have very limited range when filtered.
OMG My head is going to explode form all the choices. I thought I was all set but I cant make up my mind. Please can someone make up my mind for me. I am stuck with the HS-502, 501B, C8... I need to mount this thing to my 22LR there is no recoil with this gun. I want to operate with a pressure switch so memory mode is a must or just a straight up 1mode is good. I want to be able to light up the target but not my surroundings. Maybe I should just buy all 3??? IDK, help. I already ordered a Skyray 1JC8 and two sets of TF18650 3000mAh batteries.
:)
That happens when you start reading this forum. :)
If you are not in a hurry, wait for the first one to arrive and test it out. Then decide if you need more/less/no spill. More lumens, different switch, or whatever else.
For instance, I discovered that all of my multi-mode flashlights have memory, and I'm starting to feel that I'd prefer no memory, or at least the reliability of always turning it on in the same mode/sequence. With memory, I usually turn it on, and then cycle all modes anyway, just to make sure which mode I'm in.
Or if you are impatient, wait a week or two, then order 1 (one) more flashlight so you can test out the one that comes in first while you wait for the other. ;)
Don't order too much at once. ;)
BTW, it's easy. If you want no spill go for recoil or aspheric. Very little spill, HS-802 with XP-E (or XR-e). More lumens with larger hotspot and a bit more spill, look for Brinyte C5 with XM-L or some MRV clone. Little hotspot with a bit more spill than HS-802, go for C8.
Now, was this helpful or what? :D
Viktor
Clear as mud... 
Now I have another option and still no closer to a decision. LOL. I guess its not a big deal really. The lights are rather cheap and I can gift them if I dont like them, but who doesnt like having extra lights...
**Edit**
Ok so I made up my own mind. I already ordered a Skyray 1JC8 and two sets of TF18650 3000mAh batteries from Manafont and I ordered a C8 hi/lo T6 3C from Intl-Outdoor so now its a waiting game. Next on my agenda is to figure out how to charge the new cells that are on their way. I have a digital adjustable hobby charger that has a range from 5-70mV and .5-4.5A charging rate. Im pretty sure that the 0.5A charging rate is what I need for the 18650s? Im just not sure what the recommended low end voltatage is for charging (3.5v?) and peak voltage post charge (4.2v?)
Good luck! :)
You can safely charge Li-Ions from 3.0V to 4.2V. Charging current should be in the range of 0.5A to 1.0A. You can probably go higher, even up to 1.5A but it might shorten the battery cycle life somewhat.
If I was in a hurry I'd use 1.5A, otherwise say 0.8A or so.
Viktor