This 5mW class IIIA laser has three buttons.
It “came as an option on intimidator models between 1990 and 93 […] The intimidator forearm option was available on both 500 and 590 models. The laser uses three 1/3N batteries.”

Main photos from u/KingJungleMechanic

It should be noted that the laser can also be seen in a 1985 Mossberg Law Enforcement catalog, so the years of production apparently stretch beyond the years quoted above.

What is known is that these were certainly not offered past 1996, and likely earlier than that. It is also interesting to know that the laser was sold as a Remington 870 accessory during that same time frame, as Catalog #95107.

Being a factory option, these ~35 year old lasers are hard to come by, but not necessarily expensive. You can expect to pay marginally more for a model that has one.

The generic ‘Intimidator’ varieties:

Photos: https://bluebookofgunvalues.com

Lasers on Mossberg shotguns seemingly took a long time to return, as it was only in 2019 that they offered the Crimson Trace LS-250G Lasersaddle as a factory option on the 590 Shockwave and other models.

It is possible there were models offered with a laser between those years, but I have not been able to find them.

Sources:
Arfcom – General discussion
Reddit – Photos
Mossberg Forum – Discussion on maintenance and modding
Reddit – Filled out sticker
MossbergCollectors – PDF with model listed
GunsInternational – Sales Listing w/ Photos
GunBroker – 1985 Law Enforcement Catalog
Mossberg Site – 1997 ‘Special Purpose’ Offerings
ShootingIllustrated – 2019 Shotshow Article