I've never made any great effort to look into that specific issue but my understanding, based primarily on reading a lot of historic accounts of period ships in distress, and my memory of the accounts, is that while some ships carried rockets for emergency signaling I can't remember any lifeboats carrying pyrotechnics. Lanterns in various forms, some of which may have had lenses or glass that were colored, get mentioned but I don't remember any lifeboats from the Civil War era using pyrotechnics.
<blockquote>from Robert Welcome, NZ. Edward Wilson Very invented a "new and useful improvement in Pyrotechnic signal cartridges...". US Patent 190263 dated 1 May 1877. Very is predated by one Benjamin Franklin Coston, but Coston's gun retained the flare & was really only an ignition device and the "gun" was waved at arms length. Very's gun discharged the flare in the way we know today. In a quirk of history, Coston's son actually invented the first aerial flare launching cartridge, but his mother, jealous of the invention, lobbied against it being accepted by the Navy. Therefore Very got the credit for inventing the pistol & cartridge. Very's invention was accepted in 1882 by the US Navy & by 1900 Very pistols & cartridges were in use throughout the world. </blockquote>
Above from:
http://www.diggerhistory.info/pages-weapons/signal-pistols.htmhttp://www.radcliffe.edu/schles/exhibits/enterprisingwomen/builder/coston.htmlNo information if these hand-held flares were used on lifeboats. I sort of doubt if they were routinely kept on lifeboats as they were fairly new and likely expensive. Routine stocking of provisions and equipment on lifeboats didn't seem to be common until later.
There is also considerable ambiguity around what is meant by 'lifeboat'. The first lifeboats were rescue boats intended to be launched from shore, row through surf and weather, for the purposes of saving people on ships in distress. Lifeboat stations were fixtures along many hazardous shores.
It wasn't until much later that ships started carrying dedicated boats as a reserve means of keeping people afloat. Many ships had small boats for service and utility transport, and these would certainly be pressed into service if the ship was sinking, but, as far as I can tell, carrying boats as emergency equipment wasn't very common around the Civil War era.
I'm not sure any of this helps answer your question but maybe it will help stimulate a more complete answer form someone with more specialized knowledge.