Exactly my thought. But even Spider Farmer replied with an email stating that the number B and H is just for different regional sales. But i beg to differ.
The B's came first, and were measured in lumens, because lumens are for humans, and lm301b diodes were intended for area lights. Once LED companies started using those diodes in mass, Samsung introduced the "H" version, which they measure in umol/j, because that's you measure horticultural lights. The only difference is that they don't have the lower bin options with the H version like they do with the B version. If you are sure that your LED fixture is made with top bin LM301B diodes, it's exactly the same as using LM301H diodes. Where it gets tricky is manufactures who you can't trust to guarantee using top bin LM301B diodes, such as Mars Hydro, who has openly (and likely accidently) admitted that they do not use top bin LM301B diodes, because they would have to charge more for their fixtures as the top bin diodes are more costly for them. Basically what that means is that Mars Hydro lights will be about 10%to 15% less bright than manufactures who do use top bin diodes.