Those little LED T5 bulbs are plug and play replacements for the indicator bulbs. I think the soldering inside the bucket you refer to would be for the diode kit
https://www.kuryakyn.com/products/719/diode-kitThe diode is needed in addition to a flasher on some (but not all) LED flasher applications for the Standards and Tourers.
My switchback white to amber LED 1157 bulbs would not function correctly without having a diode installed in the bucket.