It is a bit blurry. While there is no "XY Exclusive"-Label to be found in this version, the manual ("Quick Start Guide") says: ""Purchase at Toys 'R' Us and, get $5 off Outlaw Golf for Xbox with this coupon," followed by the mail-in form with the instruction to provide the original sales receipt from Toys R Us for Outlaw Golf.
You are right that neither on the cover, in the manual, nor on the disc the exclusivity is stated; however, the manual clearly links it to Toys R Us; and since the sticker-like imprint on the cover refers to the TysRUs mail-in rebate reading "9 Holes for the Holidays! Plus $5 off the original Outlaw Golf," I assumed it is an exclusive.
If Toys R Us was the only company using this version, then it is an exclusive. Maybe others used it as well, a four page "manual" is easily reprinted, then this game isn't an exclusive for sure. I bought both versions used so I wouldn't know.
This is highly unlikely. Why would Blockbuster release two different versions (manual, cover, disc, even content) of the same game at one particular time? I assume it is actually aTRus exclusive; as you pointed out, often the exclusivity-statement is missing on the disc and/or manual, why not have one case missing it on the cover as well? The manual points clearly to ToysRUs, Blockbuster as a possibility is very unlikely.It just seemed to fit as being a Blockbuster exclusive because of all the other Outlaw Golf exclusives they had.
Thanks for pointing out the minor differences between the two versions -- to be honest I haven't plugged them in yet.