Honestly shouldn't worry much over 1915-D unless coin is EF or better with no damage around the L. And even then, Dr. Wiles would not certify any of the ones I sent him (I collect DDO-001 so needed one verified for my collection) saying he pretty much believes they are all just
DDD and no longer certifies those. Bummer, eh? But I eventually managed to get two slabbed with DDO-001 on the label as they are certainly from die 1 whether it is actually a
DDO or
DDD.
Anyway, that's the story on these "bar under L" 1915-D coins.