Altec 811B, RCF 4823 horn clones

Hello,

I bought these aluminium cast horns for few money.
I searched for a long time but couldn't find the brand and the model.

they are 51 cm width , 23 cm high , and 35 cm long,
the diameter of the throat is 20.5mm,
the frequency seems to be around 800hz

The angle is 90°,

weight is 6.6kg

the thread is 1' 3/8.

They are near altec 811b or rcf 4823....

Could someone please identify them?
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