more detail supports reimbursement of the procedure
45390 states: After the identification of the lesion, she typically administers a submucosal injection to raise the lesion, making it easier to resect, or excise, it via snare or other means. Sometimes, the provider may repeat the injection in cases of deep lesions. After the excision of the lesion, she ensures hemostasis and removes the colonoscope.
43254 states: Once a lesion has been identified, the physician performs a submucosal injection to elevate the lesion and the lesion is then resected (excised).
In order to code I would say that it doesn't necessarily need to be added, but I think that it is good documentation to always add the way in which a lesion was removed, this will support the code, and ensure that a lesser code is not applicable. It supports the reimbursement, the code assignment, and makes it clear to the next provider what was done.
As a coder, I would want as much detail as possible.