Yes. I am sure. Carbon fiber does not weaken with age.
It can be damaged by UV exposure or exposure to some chemicals. Some resins used with carbon fiber contain UV blockers for this reason. The masts of some racing yachts are made of carbon fiber and use this type of resin, since the material is exposed to sunlight for long periods. Some aircraft use components made of carbon fiber that also uses UV blockers. Further, these aircraft are painted with special primers before the color coat that is designed to completely block UV.
The material is difficult to work with due to it's 'greasy' nature (resin does not soak in well). I have worked with it myself for some aircraft parts. The stuff is expensive as well.
In most cases, for aircraft, E glass works just fine so long as there is an underlying structure. If not, S glass is required at a minimum. Carbon fiber can be used instead of S glass IF and only if the structure is under tensile load. Otherwise, it must be treated as if it were E glass.
Boeing does not sell surplus items.
In the case of being used as the pressure hull of a submarine, this is a BAD idea. It is weak in compressive and shear strength. It MIGHT last a deep dive or two, but tiny fractures will build into the structure until eventual failure. If at depth, that failure will be catastrophic compressive failure (which the Titan experienced). All aboard will be dead in literally milliseconds.
The sad part is, they were warned about just exactly this type of failure in 2018, and chose to ignore the warning.
Ironically enough, those people within the stern of the Titanic were crushed in just the same way as the stern descended to the bottom. It is the reason the stern debris is so scattered over a large area, while the bow half is largely intact (it slowly filled with seawater as it sank). Once the keel broke, the bow was already full of water and had been abandoned. The stern, with it's interior now open to the sea, sank quickly, with air pockets in much of it. Those air pockets had people in them. They crushed in just the same way as the Titan did as the stern sank.
The cause of the Titanic accident was due to several factors, including arrogance by the captain, sailing at full steam into a known ice field at night in calm sea conditions (all other ships in the area had stopped for the night); and a last second decision by the 1st officer on duty to try to port around the iceberg instead of hitting it dead on, resulting in 6 watertight compartments compromised instead of one. There was no way to avoid it. Contributing factors were a lack of binoculars for the lookouts, the iceberg itself, the calm and clear conditions masking any wave action against icebergs, and the fact that Titanic was a steamship that had stopped her engines, resulting in a loud venting of steam for about an hour, making it difficult for any crew to communicate and coordinate life boat handling. Life boat deployment was further hampered by the 5.6 degree list that had developed, and the lack of lifeboat drill and training, and the extreme cold temperature of the water, and the time of the accident (1140 pm, local time) when passengers were largely asleep.
Another chapter in the tragedy of the Titanic. What's left of the sub is on the ocean floor along with the rest of the Titanic debris field.