Are blanks normally marked with their mfr/ratings? I have a large number of blanks but have no clue as to their quality.
I've got the Rod Maker issues on CCS so this will be a help I'm sure, but do I need to know the manufacturer/ratings?
Also (forgive me I'm a newbie) they look like fiberglass blanks to me but how do I tell for sure that they are not some other material or maybe it doesnt matter?

Where did you get the blanks? If you got them on @#$%& you are probably out of luck, if you got them a reputable dealer they should have provided you with either blanks that were marked or a card listing each blanks specs.

If they did not come with the information either printed on them, included with a sticker/lable/decal and/or bag with header card, you've got seconds, blems, cast-offs, etc. All first quality blanks are marked.

Look up inside the butt end of the blank. Fiberglass will be light colored, graphite will be dark. If in doubt scrape the finish off the butt area. Graphite is grey.

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I inherited them from my brother. He passed away and I dont know where got them. I cant find any receipts, bags, labels, etc with them.

Don't worry so much about manufacturer or intended use. Just CC them and use that info to determine the usage of the blank. You can also match that up to other blanks data (Common cents database) to determine the likely origional intended usage characteristics and then build them into rods for yourself and maybe some other family members to help remember your brother by. You most likely can tell what he intended to use them for by the types of fishing he did. Fiberglass vs Graphite? More important is how you use the rod and how it fits that usage, not what material it is made of. If you do have a few fiberglass blanks then they might be perfect to build up for any kids he may have as they are likely very durable and would be great to remember their father with. Manufacturer? Without documentation your not going to have a warranty anyways so don't worry about it.