Most likely the guide in both bikes are good. Personally I would pull the front cover when you do it to insure you set the slack in the timing chain correctly there has been Rockets from the factory with one tooth off which you probably would not notice the loss of horse power unless you put it on a dyno. Now 200 miles on the engine and it did not run. My first question would be did the owner do a engine swap? and if so why. If it was the engine then I could only guess whats could be wrong with it.
Now if you go with any Carpenter stuff you will be using a modified guide and tensioner system. If not then it would depend on whether or not you changing the springs and cams or not, and how much spring tension is presented to the system.
As long as the engine did not lose it timing and had a piston and valve collision the head should be fine. If it did well then its like buying a lottery ticket as to whether the head is still good or can be repaired. Do not let this alarm you as it is a remote chance and I am speaking worse case scenario. below is a shot of a head after timing chain tensioner failure,
Note the broken exhaust valves and damage tot he head and piston in #3 and both sets of exhaust valves in #1 and #2 are bent. Of course this one did not like the broken valves standing up in the intake valve area of #3. Anyway new head cams pistons and liners in this puppy. I know I sold him the head and stuff. They say the tensioner letting loose only happens ones in a while but I have seen two already which wis enough to say the tensioner needs some safety features so it will not release. Thus the Warp9.9 tensioner modification
Personally if your 2011 has a head casting issue I can not believe Triumph has not stepped up to the plate and installed a new head on her free of charge. Especially since it is a manufactured Flaw/Failure. These things happen and depending on the quality control testing parameters on the heads it could have got by. Then there is the human error factor which I have only heard of a couple other head and block with casting failures. Only a couple though.