I figured it out. I was wrongly calculating the page size argument for gs.
Thank you very, very much again Max!

On Thu, Jun 2, 2022 at 4:41 AM Stefan Nedeljkovic <tsar.srb@gmail.com> wrote:
There is one more problem: the pdf generated has incorrect margins. I tried to manually calculate the size in ps points and run gs directly, but the results are the same. How can I get an accurate rendering of the page?

On Thu, Jun 2, 2022 at 4:22 AM Max Chernoff <mseven@telus.net> wrote:
On 2022-06-01 8:00 p.m., Stefan Nedeljkovic wrote:
> Thank you very much Max! It works indeed! One more question. How would I
> import the eps file back into MPpage, so I could do trickery with text.

Convert the PostScript file into PDF with either "ps2pdf" or
GhostScript, then you can import the file with "externalfigure":

     \startMPpage
         draw externalfigure "belgrade_gm.pdf";
         draw textext.top("One") shifted (264.352, 116.362);
         draw textext.top("Two") shifted (306.821, 186.907);
     \stopMPpage

-- Max