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See my creditpulls database in my sig -- one person applied for the IT, got declined, then applied for the secured and they used the same HP.
Also, check the Discover prequalification page -- if it gives you a small APR range (3%) it usually means an approval.
Happened to me when my Discover FICO was 610 so I just apped the secured card instead. I would rather have a $2500 secured card than a toy limit unsecured card right now -- I use my Discover a LOT (2% cash back the first year, up to 4% on some categories) and getting some meager credit limit unsecured would be useless for me.
I would say wait a few months if you want to avoid the inquiry just to get denied.
I heard it stopped working but see if you can try the Capital One upgrade link anyway -- see if they offer you a rewards card.
Also, what's your AAoA? A lot of prime creditors will deny if your AAoA is too low.