'Gain' vs. 'Have'

[a player]

It has been made clear that 'Gain' and 'Have' are keywords to which we must pay special attention in Shadow Era, but it is not always apparent to me how they work.

Amber Rain will cause a target weapon to 'gain' two attack points, but prohibits that weapon from 'gaining' any other bonus.

Reserve Weapon does not cause an attack gain, but indicates that your weapon 'has' an extra point of attack while RW is in play. If the player chooses, s/he may pay zero SE to retrieve a target weapon from the Graveyard with a plus-one attack, destroying RW in the process.

Since neither aspect of RW mentions gain, one might believe that they are both allowed to operate on Amber's weapon along with the ability gain, but this not the case. If both aspects of RW were regarded as 'bonuses' then neither would be allowed to influence her weapon.

In light of the present wording of Amber Rain and Reserve Weapon, when and why should RW sometimes stack with Amber's ability, and sometimes not? Please provide examples using Jeweler's Dream.

[Gondorian]

Hi. I'll work on an answer for you ...