The general consensus with the corroborating claims is yes. The Iran-Contra conflict specifically was centered on this particular type of scandal. The CIA and military were allegedly funding Contra rebels in staging the overthrow of the Sandinista government that was then distributed and sold in global markets, and used to provide the Nicaraguan Contras with weapons and training in El Salvador, Guatemala, Honduras through a CIA asset named Danilo Blandon.
If you’re familiar with the gist of CIA crack and Contra scandal, the precursor to the Iran Contra scandal was the flood of cocaine from South American cartel’s into America.
At the time Danilo was a growing player in the crack and cocaine market. He met a drug dealer from California who would later go on to be known as America’s longest operating king pin, ‘Freeway’ Rick Ross.
Danilo became Freeways sole supplier and together they ran a very successful network from 1980, when he became connected with Contra elements in America, and 1986, after he was involved in a sting to bust Freeway.
Danilo was allegedly the CIA’s inside person within the Nicaraguan landscape at the time, and seems to have had pretty extensive access to information to shield his cocaine business along with methods to safely and consistently get his shipments delivered.
In terms of hard evidence supporting the claim, it’s mostly verbal testimony of Danilo and anecdotal evidence provided by Freeway, corroborated by Gary Webb and elaborated upon in his book Dark Alliance.
To provide a small caveat – the CIA was an incredibly powerful, unrestricted intelligence agency carrying out elaborate coups of governments all over the world, particularly in communist regimes.
For them to cover up a hard trail revolving around a single contact point isn’t a huge stretch. The combination of Danilo’s clear inside information that allowed him to evade state and federal investigations for many years, the strange suicide of Gary Webb and the media campaign that preceded it, along with the publicly favorable reporting on Contra elements, it later became an open secret that the US had supported Contra elements, and the only mechanism to fund outside groups with equipment without discretion was the CIA.
In 1989, John Kerry would publish an almost 1200 page report providing evidence of ties between intelligence agencies and the US government and rebel Contra groups.