Re-use Shimano quick link?
If I understand correctly you want to buy a new chain and re-use your previous masterlink. I'd strongly advise against.

The reason for NOT re-using an old masterlink with a new chain makes sense. Chains are commonly replaced because they are worn. The links are lengthened with time and above a 1% lengthening the chain is considered over the top. The masterlink is worn at the same rate. Now if you use an old masterlink on a new chain you'll have ~110 links of the correct length and one that is longer. The smallest annoyance may residde in a noisy drivetrain. The worst will have the chain skip at each time it reaches the sprockets and once again it reaches the rings.