Old, and late, but no, this is not a thing, especially since not all CDN downloaders used the exact same templates for their tickets, so hashes can differ even if the contents and tmd are valid.
If you need to verify updates and dlc, use the CIA checker in GM9. As long as tmd is legit and the checks pass you're good.
Note that (standard) dumps made through GM9, while they work fine on console, they are not valid for archival purposes, because they are decrypted and no longer match original eShop contents. You can get all updates and dlc via ctrcdnfetch instead (in the case of dlc though, the CIA will likely fail to build if all the DLC is not yet available.)
Either that, or if you've bought the DLC or installed the updates yourself, you can make a (legit) dump through GM9, and zero out the console ID from the ticket. GM9 (legit) dumps retain all encryption, but you can't install a CIA which has a non-zero console ID in the ticket, so you have to zero it out (unless Luma updated at some point to patch out those checks.) This makes the ticket illegit, but it's the best you can realistically get if you want your dumps to be actually useable.
Okay, this is all great information. Thank you very much!
Assuming I have some time and some data processing background, would it make sense for me to go through and get all the DLC/updates using the method below
Either that, or if you've bought the DLC or installed the updates yourself, you can make a (legit) dump through GM9, and zero out the console ID from the ticket. GM9 (legit) dumps retain all encryption, but you can't install a CIA which has a non-zero console ID in the ticket, so you have to zero it out (unless Luma updated at some point to patch out those checks.) This makes the ticket illegit, but it's the best you can realistically get if you want your dumps to be actually useable.
Generate hashes, and contribute to the existing datfiles? Seems having a dump using the method above would be identical across the board with maintained data integrity for everything other than the console ID.
I'm not an expert with any of these files formats, though (.3ds or .cia), so maybe this is somewhat naive.