It's up for debate, but if you ask me, they should have plenty.
Hamas is surprisingly good at smuggling weapons, some of the most common weapons after the Type-56 AK is none other than the Menusar (shortened Colt 503) that they smuggled in quantity from the IDF, together with the Matador rocket launcher.
M72 + Matador, a few more M72 has also been captured from the IDF in the ongoing war
So if they could smuggle all that stuff from mortal enemy israel, I suggest they can smuggle more from Egypt, which while at the top level is clearly having animosity with Hamas (being affiliated with Muslim Brotherhood), at the bottom, they could rely on the Egyptian low ranking troops which I believe has been their main supplier of arms in addition to the traditional black market dealer. Low-paid soldiers are surprisingly willing to sell weapons to their foes, as can be seen in this picture where OPM brandished their rifles which are open secret to be sourced from Indonesian low-paid soldiers and police.
OPM Pindad SS-1 and Norinco AK-2000P which could only be sourced from none other than Indonesian army and police arsenal
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Most of Hamas's domestic weaponries are made from readily available ingredients (sugar, fertilizer, etc) so they're still good to go for many more months.
Back during the Mosul campaign, ISIS readily make thousands of home-crafted rocket launchers, some even with in-house explosive penetrator design
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I believe Hamas's subterranean weapons workshop deep inside those tunnels is more protected than the surface weapons workshop of ISIS during the battle for Mosul + I suspect they have stored the necessary ingredients to keep producing even in war time.
Another indicator to "guess" how much longer that Hamas will be supplied with anti tank rocket is this article from 2009
Flickr/Creative Commons/apdk The intricate network of tunnels connecting the Gaza Strip with Egypt remains the lifeline of Hamas, allowing it to build up its weapons arsenal and indiscriminately fire rockets into Israel. Some sources estimate that as many as 800 tunnels crisscross the border...
www.aei.org
from September 2005 through December 2008, that number increased drastically: Israeli intelligence sources estimate that 250 tons of explosives, 4,000 RPGs, and 1,800 rockets crossed the border during that span.
Since then a lot has changed, in 2011 Gaddafi Jammahirriya finally fell, and so has the locks of his massive arsenal which included AK-103 that
@Kartal1 in addition to rare F2000 rifle and the IGLA-S MANPADS.
Hamas gunmen with F2000s and Ak-103. All ex-Jamahiriya stock
and I'm sure as well many ex-Libyan army RPGs finds its way to Gaza through Egypt.
So that + Hamas own production, should be good for a long protracted urban war