Diifference between INA827AIDGK & INA827AIDGKR
They are identical. The difference is the packaging, as described in the datasheet. Do not depend on distributor data- the manufacturer's data is the only one you should consider correct (and even then...) 



INA827AIDGKR quantity 2500 is packaged in a full-size tape and reel 

INA827AIDGK quantity 80 is packaged in a tube