[is/was] the first one

I have made up the sentences below.

(1a) I said to Jack, "I have bought some special edition Coca Cola bottles over the past five years. One of them was colourful. That was the first one I ever got.

(1b) I said to Jack, "I have bought some special edition Coca Cola bottles over the past five years. One of them is colourful. That is the first one I ever got.

Some of my non-native English speaking friends think "was" is correct because the past tense is used throughout the example. However, my other friends think "is" is correct because what is said is factual and is still true. From (1b), one of the bottles is still colourful unless you have changed the original coloring. In addition, the fact that you hadn't got any bottles before the colourful one can never be disproved.

Both groups of my friends have given me acceptable explanations about the correct tense. Please explain which tense is correct. Thank you very much.