The three things of interest are:
1) The large-ish ferrite rod antenna. With antennas, size does matter.
2) The three gang tuning condenser. As a general rule this implies a tuned RF amplifier ahead of the mixer (kudos to G3RZP). This means one gang (usually the one with the largest plates) resonates the loopstick at the intended frequency, the next peaks the RF amplifier to match, the third tunes the local oscillator. If this had been an AM / FM radio there would be a minimum of four gangs but since it's AM only the third gang tells you there's an extra tuned stage up front.
3) Count the number of "IF cans". The green slug jobbie in the lower left probably couples the RF amp to the mixer stage while the red can slightly to its right is the local oscillator coil. So what's up with the remaining three cans? Two stages of IF amplification plus a detector coil (the two IF cans are on either side of the speaker magnet). With two tuned stages in the front end plus three tuned stages in the IF / detector, the radio should be noticeably more sensitive and selective than the typical AA5 or six transistor pocket portable where the antenna circuit connects directly to the mixer and there is only one IF coil plus one detector coil.
If we had a schizmatic we could confirm this, but if what I suspect is true there are no ideas in the Browni that haven't been used in high end receivers since the early 30's by RCA, Zenith and others. You just don't see it very often in a 60's vintage pocket portable, aside from a few high end Zenith and Motorola designs.
Which is why Zenith Royale transistor radios tend to fetch premium coin. You can read the PC board on a yard sale radio by noticing things like this to pick the winners from the runner-ups in terms of design sophistication......