You could do that however if you need to know the order those evens occurred. e.g. you are back testing how one instrument can be used to trade another, you need total ordering.
For back testing purposes I suggest extracting the information you need into a queues, or flat files, or matlab/vector format for repeated replay. That way only the data appropriate for your backtest is needed. Given you will be performing the replay many, many times it can be useful to cut it down to only the data you need in a compact form. e.g. you might use float or short+fixed precision data.
Regards, Peter.