It’s not obvious where the alternative numbering comes from, but the datasheet representation is generally correct. In any case, the diode test function available on most multimeters should let a person remove doubt in a few seconds.
That would seem reasonable, considering that the diode could be expected to burn on the order of 12W under the stated maximum conditions. It should be understood however, that heat sink ratings are (necessarily) based on a lot of stated or implied assumptions that may or may not align with one’s particular circumstances. This post may offer insights on the topic.
That’d be light work for one of the diodes in the package individually, so the question of whether or not two in parallel would share equitably seems irrelevant in this case.
It may be of benefit to zoom out a bit and consider the context of how & why you’re thinking of using the device in the first place. After all, it doesn’t really matter how well one carries out the details if the overall plan is ill-fated…