Of course it's an accomplishment, even if others did it long ago. If I successfully run my first marathon (unlikely), it'll still be an accomplishment even though someone else first did it 2500 years ago. Getting a spacecraft into Mars orbit takes skill and careful work. I think it clearly warrants congratulations.
Also, by the way, the first Mars orbiter wasn't in 1965—that was the first successful flyby. The first successful orbiter was Mariner 9 (https://en.wikipedia.org/wiki/Mariner_9) in 1971.
Maybe I should rephrase. Is this mission a scientific achievement? It could be a economics/accounting/marketing/HR/logistics achievement, but what is new scientifically?
In the age of NSA sponsored spying, having an independent and largely self-taught space program is indeed a scientific achievement. Especially for a country that's 67 years old.
do you understand enough "science" to fathom "scientific achievement"? If the people behind the mission explained to you "science" in it and what are the "scientific achievement", would you understand them?
Let's put aside the science, because they haven't taken the data they wanted yet, so it's impossible to debate, and indeed somewhat beside the point for this 15kg instrument.
The thing about spacecraft is that there is a huge engineering component. The s/c is in a novel environment (vacuum, radiation, cold) and many systems have to work together. You have to figure it all out in advance, using first-principles physics and modeling, and design and build a system that works without further manual intervention. Just getting it there intact is a significant achievement in systems engineering.
Technology demonstration is what this mission was about.
Also, by the way, the first Mars orbiter wasn't in 1965—that was the first successful flyby. The first successful orbiter was Mariner 9 (https://en.wikipedia.org/wiki/Mariner_9) in 1971.